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From page 2... ...
SUMMARY: INSPECTION MANUAL After the Cold War, the technology transfer initiatives taken by the federal government to use the unused manufacturing capacities of composite manufacturers in the military and space industries resulted in the proliferation of fiber reinforced polymers (FRP) usage in the bridge industry.
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SECTION 1: INTRODUCTION 1.1 PURPOSE OF THE MANUAL This manual presents guidance for inspection and assessment of in-service fiber reinforced polymer (FRP) bridge decks.
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3Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 1.3 INTENDED USERS This manual targets practicing bridge engineers and inspectors who inspect, assess, or evaluate FRP decks. The manual provides comprehensive information on FRP materials, compares them with conventional bridge materials, identifies specifics of various FRP deck configurations, highlights important elements and details of FRP decks and related components, identifies inspection and assessment methods for observed damage, and provides methods for correlating these assessments to uniform rating factors for use in assessing bridge elements.
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manual, and the manual organization. In addition, this section provides guidance on how best to use this manual.
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5Field Inspection of In-Service FRP Bridge Decks: Inspection Manual This section introduces the manual and provides guidance in using the manual for inspection purposes. Section 2 of the manual introduces both seasoned inspectors and inspector trainees to FRP material and its general construction uses.
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Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 6 HOW TO USE THIS INSPECTION MANUAL LOOKING FOR...? GO TO MANUAL SECTION If you are already familiar with FRP material and deck types, manufacturers, and processes Section 4 To familiarize yourself with FRP material Section 2 To familiarize yourself with FRP deck types, details and construction Section 3 To familiarize yourself with fabrication and construction details and components Section 4 To familiarize yourself with common terminology Glossary To learn what inspection methods are available, their costs, and the scope of their application Section 5 To learn how to record and file and to review a list of things to inspect Section 6 To learn how to use the inspection results to rate the condition of the deck Section 7
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SECTION 2: FRP MATERIAL 2.1 HISTORICAL PERSPECTIVE FRP composite materials consist of two or more distinct constituent materials with recognizable interfaces between them. The constituent materials are intentionally combined to "engineer" a desired set of properties in the composite material so that it can perform its functions optimally.
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Bridge Research Program projects as of 2003. These are in addition to installations under separate federal agency programs such as DARPA (Department of Defense Advanced Research Projects Agency)
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9Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 2.3.1 BASIC CONSTITUENT COMPONENTS OF THE LAMINATE At the macro level, FRP composite materials are composed of two primary components: a polymer matrix resin and fiber reinforcements. Additives and fillers that enhance particular characteristics of the system are a third component.
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4. Epoxies Epoxies differ chemically from polyester resins and cure through a different reaction process.
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11 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 2.3.1.2 Fiber Reinforcement A variety of reinforcement fibers have been developed in the composites industry, but to date only a few -- namely, E-glass fiberglass and high-strength carbon fibers -- have made it to commercial use as commodities, mainly because of cost and broad availability. Table 2.3.1.2-1 compares the mechanical properties of these and other fibers, which may in the future see their way into deck construction.
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These are wound onto spools as continuous strands and may be directly used as structural reinforcement in processes such as filament winding and pultrusion. Components having only rovings aligned in one direction will have highly unidirectional mechanical properties.
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13 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 3. Woven Rovings Woven roving is produced by weaving fiberglass rovings into a fabric.
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5. Non-crimp Fabric By stitching or knitting the reinforcement strands together using lightweight threads, sheets of fabric can be made without weaving to produce straight, non-crimped, layers of fibers (see Figure 2.3.1.2-5)
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15 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 2.3.2 OTHER MATERIALS In addition to the constituent materials, other materials may be introduced into the FRP material or added to the composite laminate as enhancements to improve specific properties of the FRP material. A short list and basic description of these components are given in the following sections.
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Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 16 2.3.2.3 Gelcoat Gelcoat is a thick resin overcoat applied to finished FRP components to improve either surface properties or surface finish, or both. The coating can be of a different resin than the matrix resin, one that is filled with UV inhibitors or fillers to improve surface toughness and weathering characteristics.
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17 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Figure 2.4-1 34-ft.
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SECTION 3: FRP DECKS AND INSTALLATION PRACTICE 3.1 INTRODUCTION Historically, composite materials -- FRP in particular -- have been used extensively in many areas, ranging from highly complex aerospace and military applications to more routine applications such as liquid storage tanks, fishing rods, and truck bedliners. Due to their low weight, high strength, and significant durability advantages, the most prevalent nonconsumer use of FRP material has been in the military aviation and civilian space applications.
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19 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 3.3 TYPES OF FRP DECKS Based on their composition, FRP decks can be divided into three categories: honeycomb sandwich, solid core sandwich, and hollow core sandwich. 3.3.1 TYPE 1: HONEYCOMB SANDWICH This type of deck is shown in Figure 3.3.1-1.
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3.3.3 TYPE 3: HOLLOW CORE SANDWICH The third type of FRP deck consists of pultruded shapes fabricated together to form deck sections. These FRP decks typically have continuous hollow core patterns as shown in Figure 3.3.3-1.
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21 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 3.5 DISCUSSION OF MANUFACTURING METHODS AND DECK TYPES When fabricating components and structures from traditional construction materials, manufacturing is usually a matter of shaping, removing, and joining materials that are already solid. With FRP composites the situation is somewhat different than with metalworking (and, in some very specific ways, similar to casting)
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The advantage of hand lay-up is its low capital equipment costs and the low-to-moderate labor skill it requires. These factors usually make it the least expensive method for oneof-a-kind or limited production work.
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23 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 3.5.2 VACUUM-ASSISTED RESIN-TRANSFER MOLDING The VARTM method employs a soft bag over the part to seal the mold so that a vacuum can be drawn under the bag. Once vacuum is achieved, the part is pressed onto the hard tool by atmospheric pressure.
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wrap-around shapes to be designed and details such as hollow tubes and trapezoids to be produced. Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 24 *
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25 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual As in the pultrusion process, filament winding is an economical method for manufacturing tubular structures and structural columns. Once the setup is complete, the winding process can be autonomous almost from start to finish, with the preferred winding pattern and number of back-and-forth motions preprogrammed into a process controller.
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3.6 GENERAL DELIVERY AND INSTALLATION PROCEDURE Installation procedures for all deck types follow similar guidelines, which include 1. Delivery and acceptance inspection of the FRP decks, 2.
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27 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 3.7.2 INSTALLATION PROCESS For typical FRP decks, all suppliers and contractors follow similar installation procedures. The following general sequence of events applies: 1.
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3.7.3.1.1 Interference Fit with Shear Keys This method uses an insert or filler material in between decks to effect a shear lock between decks. This is similar to interlocking used between precast concrete slabs where grout is poured between the channel cavities of adjacent slabs to serve as shear keys.
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29 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Several approaches have been used to dress the connection and smooth the transition. In the King's Stormwater design, the shear key grout was filled flush to the surface and then overlaid with polymer concrete.
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Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 30 Figure 3.7.3.1.2-1 Tongue-and-groove shear key deck connection on Schuyler Heim deck. Figure 3.7.3.1.2-2 Tongue-and-groove connection on pultruded deck.
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In general, the installation procedure involves the following steps: • Prepare the surfaces of the joining faces, • Apply the adhesive to one of the faces, • Press the decks together to squeeze the joint shut and smear the adhesive over the contact faces, and • Let stand until cured. 3.7.3.1.3 Butt Joints with Shear Splice Plate Strips This method uses a butt joint between adjacent decks with splice plates field-bonded to the top and bottom of the decks to transfer load as shown in Figure 3.7.3.1.3-1.
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3.7.3.2 Joints Between FRP Deck and Superstructure The following sections discuss different details typically used to connect the decks to the superstructure. 3.7.3.2.1 Shear Stud Connections This connection is adapted from the method used to anchor precast concrete slabs onto steel girders in which Nelson shear studs are welded onto the top of the steel girders through holes bored into the top and bottom facesheets of the composite deck (Figure 3.7.3.2.1-1)
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33 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual with grout to lock in the studs and deck. This setup is repeated down the length of the girder in a predetermined spacing based on design requirements.
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3.7.3.2.2 Cast-in-Place Connections This connection is similar to the shear stud connection except that a different shearing member is used. In the King Stormwater bridge, a set of bent reinforcement bars cast into the underlying concrete-filled tubular girders act as the shear studs.
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35 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 3.7.3.2.4 Bolted Connection This connection uses threaded Nelson studs to anchor composite decks onto steel girders. Like the shear stud, the threaded stud is welded to the girder through predrilled holes in the deck, as shown in Figures 3.7.3.2.4-1 and 3.7.3.2.4-2.
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3.7.3.3 Joints at Approaches Approach joints for FRP decks range from open joints to soil backfill abutting the FRP decks. In some cases, conventional elastomeric materials have been used for the joints.
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37 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 3.7.5.2 Curbs and Railing on Independent Structure On some bridges, curbs and railings are designed to be independent of the FRP decks. In these installations, the curbs and railings are connected to independent superstructure components or fascia girders.
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3.7.5.3 Curbs and Railings on Independent Structure but Connected to FRP Deck On many FRP deck bridges, the railings are connected to independent fascia beams or girders but are also indirectly connected to the FRP decks. In these types of construction, the curbs are typically built on the FRP deck as discussed in an earlier section, while the railings abut the curbs but are connected directly to a fascia girder.
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39 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual SECTION 4: SIGNIFICANT DECK DETAILS AND DAMAGE TYPES 4.1 OVERVIEW This section presents FRP deck details and damage types and, in conjunction with Section 3, allows the inspector to understand the areas that need special emphasis during inspection. It also prepares the reader to understand the inspection techniques presented in Section 5.
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problems generally occurs at the deck connections in the form of overlay/wear surface cracking or spalling. 4.2.1.1 Interference Fit with Shear Keys The main concern with the interference fit in this type of connection is the eventual "loosening" of the joint.
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41 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual For all these conditions, some of the main indications of problems would be • Cracks in the overlay or wear surface; • Noticeable deflections in one abutting deck element and not the other; • Elevation differences between the edges of the decks; • Crippling of the flanges that may indicate joint movement; • Large gaps at the seam-line, signaling joint movement; and • Water seepage on the underside of the deck. 4.2.1.3 Butt Joints with Shear Splice Plate Strips Inspection concerns for butt joints are similar to those in other connections, with additional concerns stemming from the bonding sensitivity of the splice plate strips.
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to those connection details and inspection methods being used successfully on existing decks. The most common types of connections now in use are • Shear stud connections, • Clip connections, and • Bolted connections.
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43 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual • Again, any unusual localized vertical motions may indicate a weak or failed connection, so take steps necessary to diagnose the problem. 4.2.2.3 Bolted Connections The same inspection issues covering shear stud connections apply here as well.
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4.2.3 APPROACH JOINTS Approach joints or deck components adjoining these areas on FRP decks are typically prone to damage due to differential movement between the approach and the deck. Both environmental and vehicular loading effects can cause this differential movement between the approach and deck.
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45 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 4.2.4 WEARING SURFACES Important areas for inspection of wearing surfaces include areas around interfaces such as scuppers, curbs, and approach joints. Areas over panel-to-panel joints also are susceptible to damage or deterioration.
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4.3 DECK PANEL INTERNAL DETAILS Most FRP decks are made with fiberglass reinforcement in polymer resin, and only in special cases are stiffer and more costly carbon fibers used. As discussed in Section 3, the stiffness of fiberglass structural laminates typically ranges from about 2.0 to 2.5 million psi, which is similar to concrete in compression.
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47 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual • Visible motion under traffic loads, which may indicate detachment of the wear surface or even the facesheet from the core. 4.3.2 SANDWICH CORES The design of the deck core is generally what distinguishes the manufacturer and fabrication process of the FRP deck.
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4.4.1 BLISTERING Blistering appears as surface bubbles on exposed laminate surfaces or gelcoated surfaces as shown in Figure 4.4.1-1. In the marine industry, blisters are generally attributed to osmosis of moisture into the laminate that exerts local hydrostatic pressure between layers, causing delamination and subsequent bubbling.
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49 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual More commonly, voids would be hidden and become the site where delamination begins over time. An example of a severe void is shown in Figure 4.4.2-2.
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• Chemical reaction, surface deterioration due to prolonged UV light exposure, or exposure to intense heat or fire. • Crazing and whitening from excessive strain, visible mainly on clear resins.
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51 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 4.4.6 CRACKS Damage due to impact can result in cracks on the facesheet emanating from the point of impact. Impact cracks are caused by impact from vehicles, debris, or stones, and they typically result in separation of material through the entire thickness of the laminate.
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4.4.7 SCRATCHES Facesheets can be abraded through improper handling in storage, during construction, with tools, and so forth, and this can result in scratches or shallow grooves on the FRP surfaces. These are usually just unsightly surface blemishes, but, if severe, they can develop into full-depth cracks under vehicular or environmental loads.
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53 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual SECTION 5: INSPECTION 5.1 TYPES OF INSPECTION Various types of inspection techniques can be used to observe and note the condition of FRP decks. This section identifies eight available nondestructive evaluation (NDE)
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5.1.2 TAP TESTING Tap testing is the second most common type of NDE test performed on FRP bridge decks. Tap testing is fast, low in cost, and effective for inspecting composites for delaminations or debonding.
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55 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual internal geometry. Instruments required for tap testing are a flashlight, a measuring tape, a straight edge, markers, and a large coin or small hammer.
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The thermography process is quite simple: it consists of filming the object exposed to sunlight with an infrared video camera or using a combination pulsed flash/infrared camera unit (Figure 5.1.3-2)
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57 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 5.1.4 ACOUSTIC TESTING In acoustic emission testing, an elastic wave is generated by the rapid release of energy from within a material. A structure under certain load levels produces acoustic sound, usually in the range between 20 KHz and 1 MHz.
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that AE testing and the follow-up localized NDE testing will be contracted out. Typical discontinuities detectable by AE include delaminations, debonding, and fiber breakage.
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59 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 5.1.6 RADIOGRAPHY Radiography uses a penetrating radiation source such as X-rays or gamma rays and radiographic film to capture images of defects. Differential absorption of the penetrating radiation by the specimen will produce clearly discernible differences when recorded on radiographic film.
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A stiffness sensitivity analysis is performed to evaluate stiffness changes in the structure by determining the damage location index. The damage index identifies local potential damage of structural members.
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61 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual The scope of load testing can vary depending on the purpose it's meant to serve and the resources available. For the purpose of inspection -- that is, to verify bridge performance and detect potential damage for condition rating -- limited-scope proof testing may be reasonable and manageable within the scope of a periodic inspection program.
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5.1.9 COMPARISON OF METHODS Potential inspection methods for FRP decks have been identified from aerospace technology, defense technology, shipbuilding, pressure vessels, and bridges. Detailed descriptions and discussions on the inspection methods are presented in the preceding sections.
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63 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual While the hourly rates above for inspection labor are representative for inspection staff skilled in these methods, additional daily fees ranging from a few hundred dollars to $1,000 or more may accrue for procuring equipment or support for these more complex, capital equipment–reliant inspection methods. The visual method is by far the simplest and most important technique for inspecting FRP decks.
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bridge inspection programs. Bridge owners are more likely to contract out for these services when needed.
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65 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 2. Internal details: The FRP deck section itself, including the facesheets, cores, web components, and panel edges.
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Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 66 Figure 5.2.1.1-1 Reflective cracking and oozed material at FRP deck-to-deck joints. Figure 5.2.1.1-2 Debonding at joint and below wear surface.
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5.2.1.2 Deck-to-Girder Connections The deck-to-girder connections are important parts of FRP deck bridges since the structural behavior of the deck is contingent on proper connection between the deck and the support structures. In addition, the connections are usually made using mechanical fasteners, which tend to work better with conventional material such as steel and concrete than with FRP.
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should be marked and monitored visually or with measuring instruments to determine whether it is active in response to traffic or other live-load application. • On the underside of the deck, look for any separation between the deck and the haunch or other supporting superstructure component.
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69 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Figure 5.2.1.2-1 FRP deck and connection studs. Figure 5.2.1.2-2 Clip type connection.
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5.2.1.3 Approach Joints As discussed in Sections 3 and 4, approach joints on most FRP deck bridges consist of soil fill abutting against the side of the deck; formed or other elaborate joints typically are not used. Despite the rudimentary nature of approach joints on FRP deck bridges, the following steps should be performed as a minimum, when inspecting them: • Observe the approach joint area for differential movement between the deck and approach.
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71 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual of the deck. The wearing surface inspection, at a minimum, should include the following activities: • Chain drag is an effective way to locate distressed areas of the wearing surface.
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5.2.1.5 Curbs, Sidewalks, Parapets, and Railings Curbs, sidewalks, parapets, and railings are susceptible to horizontal loads and impacts. Typical curbs, parapets, and railings are shown on Figures 5.2.1.5-1 and 5.2.1.5-2.
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73 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual • If distress is identified on any FRP components, then investigate the distress areas further with advanced inspection techniques. Conducting further inspection is important, as the visible damage may be only a small portion of actual damage within the FRP deck.
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Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 74 Figure 5.2.1.5-2 Typical concrete parapet. Figure 5.2.1.5-3 Underside of railing showing connection of railing to deck.
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5.2.2 INSPECTION OF INTERNAL DETAILS As discussed in Section 4.3, FRP decks are largely sandwich panels composed of the following sub-elements: • Top facesheet external laminate, • Center core section and its components, • Bottom facesheet external laminate, • Panel-to-panel connections, • Secondary components such as closeouts, and • Penetrations and holes. Visual access to all of these sub-elements is generally restricted because of the box construction of decks.
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What is important are the appearance and performance of the deck system in service. Aside from the wear surface, visual indicators of problems or potential problems may not appear immediately after installation, but arise over time.
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77 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual facesheet and core and may appear similar to delamination. Buckling occurs when the facesheet snaps through, but can recover flatness.
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Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 78 WATER OUT OF HOLES Figure 5.2.2.1-3 Punch-through of the deck from impact (Schuyler Heim Bridge)
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79 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Figure 5.2.2.1-6 Facesheet delaminations and buckling at maximum load. Figure 5.2.2.1-7 Tearing of core leading to facesheet buckling.
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5.2.2.2 Sandwich Cores Visual inspection of sandwich cores and web components is unlikely since they are typically sealed within the facesheets. Inspecting these components therefore entails the use of advanced techniques such as radiography or indirect methods such as impulse response and load testing.
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81 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 5.2.2.3 Edges and Closeouts Edges and closeouts transfer shear across panel-to-panel joints or carry the reactions at the supports. In addition, and depending on the connection or support details, these regions also see rotational and torsional loads.
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SECTION 6: RECORDKEEPING This section elaborates on a uniform method of annotating and describing damage and findings of FRP deck inspection. 6.1 NEED FOR STANDARD NOMENCLATURE FOR PARTS, LOCATIONS, AND DAMAGES In order to have uniformity in recording and evaluating field conditions, both across various structures and over time on the same structure, there is a need for standard nomenclature to describe the location, parts, and condition of the FRP components.
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83 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual rating used should be the same for all other bridge components. One such scale is prescribed in FHWA's Recording and Coding Guide for the Structures Inventory and Appraisal of the Nation's Bridges.
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• The continued presence of causal elements. • Information on any noticeable change in behavior of the deck due to observed condition or damage.
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85 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual • Manufacturer's specifications and other manufacturing information about the deck material and composition; • Detailed drawings; • Deck connection details and specifications for any adhesives used; and • Material specifications for FRP deck. 6.4.2 CHECKLIST OF DETAILS AND ITEMS TO BE INSPECTED The checklist of external details (deck structure)
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• Voids; • Discoloration; • Glossiness; • Cracks; • Delamination; • Presence of moisture; • Abrasion or tearing; and • Creep, flow, or rupture. 6.4.4 INSPECTION AND TEST METHODS CHECKLIST The inspection and test methods are as follows: • Visual inspection and testing, • Tap testing, • Thermal testing, • Acoustic testing, • Ultrasonic testing, • Radiography, and • Modal-parameter analysis.
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87 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Inspection/Damage Detection Methods Used Yes? Detailed field note page reference Instrument(s)
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Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 88 Damage Types Observed Yes? Detailed field note page reference Is the damage active?
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89 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Yes? Detailed field note page reference Is the damage active?
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Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 90 Yes? Detailed field note page reference Is the damage active?
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SECTION 7: CONDITION ASSESSMENT This section provides procedures for condition assessment, evaluation, and rating of FRP deck conditions observed in the field. 7.1 CONDITION RATING OF FRP DECKS The basis for rating condition of FRP bridge decks provided in this manual parallels contemporary inspection and rating practice for bridges constructed of traditional materials.
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7.1.1 GUIDELINES FOR ASSESSMENT AND CONDITION RATING OF FRP DECKS Tables are presented below for distilling inspection results from the inspection forms presented in Section 6.5 into deck element ratings. The tables and guidelines presented below are a qualitative measure for systematically translating the physical damage identified through inspection to a condition rating for the structure.
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93 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual – Joints, including panel-to-panel joints, panel-to-girder joints, and approach joints are rated. Deteriorating FRP deck joints can display separations and openings between elements, cracking and movement of joints, and damages to deck elements in the vicinity.
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loads. The top facesheet is the first structural element that will require scrutiny upon the discovery of any deterioration or signs of damage on the wear surface.
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95 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual For simplicity, if one limits the flange thickness to two sizes, say 1⁄4 in. and 1⁄2 in., then the critical delamination size will be in the range of 8 in.
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Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 96 Rating Code Condition Description 9 Excellent Excellent condition, typically new construction. 8 Very Good No significant problems noted.
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97 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Rating Code Condition Description 9 Excellent Excellent condition, typically new construction. 8 Very Good No significant problems noted.
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Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 98 Rating Code Condition Description 9 Excellent Excellent condition, typically new construction. 8 Very Good No problems noted.
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99 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Rating Code Condition Description 9 Excellent Excellent condition, typically new construction. 8 Very Good Small and superficial wear, deterioration, or collision damage.
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Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 100 Rating Code Condition Description 9 Excellent Excellent condition, typically new construction. 8 Very Good Minor cracking less than 1/32 in.
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7.2.1 EFFECTS OF VEHICULAR LOADS Evidence of the effects of vehicular loads can be divided into two distinct categories: (1) damage due to normal vehicular traffic over the bridge and (2)
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facesheets will punch through by failing around the perimeter of the applied load, shearing off the FRP material directly beneath the applied load. 7.2.3 EFFECT OF ENVIRONMENTAL AND OTHER LOADS Environmental loads (e.g., temperature, radiation, and moisture)
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103 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 7.2.3.1.3 Freeze-Thaw Effects Within the normal temperature range, freeze-thaw typically has little effect on low-voidratio composites, since a low void content keeps frozen moisture from being absorbed by the FRP and causing any appreciable damage. However, even with a low void ratio, severe thermal cycling can cause microcracks to form and grow.
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plasticize. Absorption of water by FRP and freeze-thaw cycles thereafter can result in freeze-thaw-initiated damage of FRP decks.
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105 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual worst-case fatigue condition. In most cases, the sections of FRP decks would be subjected to zero-tension or zero-compression cycles due to the on-and-off nature of traffic loads, so fatigue conditions would be far less severe.
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SECTION 8: CASE STUDY OF THE SALEM AVENUE BRIDGE The Salem Avenue Project (1999) was an ambitious project to use FRP composite decks on an existing State Route 49 bridge spanning the Great Miami River just west of downtown Dayton, Ohio.
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107 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Figure 8-1 Walk-through inspection on Salem Bridge; wear surface cracking and spalling observed. Figure 8-2 Wear surface lift on deck.
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From page 109... ...
Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 108 Figure 8-3 Observed blister location on deck. Figure 8-4 Water spouting out of drill holes on deck.
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From page 110... ...
109 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Figure 8-5 Haunch inspection shows deck rise. Figure 8-6 Tap tests indicate debonding of facesheet.
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From page 111... ...
Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 110 Figure 8-7 Coring through deck. Figure 8-8 No adhesive between facesheet and core webs.
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From page 112... ...
111 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Figure 8-9 Coring of deck reveals detached facesheet. Figure 8-10 Water accumulation in cavity of deck.
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From page 113... ...
GLOSSARY OF COMMON COMPOSITES INDUSTRY TERMS Adhesive – Substance capable of holding materials together by surface attachment. Adhesive types include a monomer of at least one of the polymers to be joined, catalyzed to produce a bond by polymerization; solvent cement that dissolves the plastics being joined, forming strong intermolecular bonds, and then evaporates; bonded adhesives or solvent solutions of resins, sometimes containing plasticizers, which dry at room temperature; and reactive adhesives or those containing partially polymerized resins (e.g., epoxies, polyesters, or phenolics)
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From page 114... ...
113 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Clay filler – Naturally occurring sediments rich in hydrated silicates of aluminum, predominating in particles of colloidal or near-colloidal size. Those of particular interest to the plastics industry such as kaolin or china clay are used as fillers in epoxy and polyester resins.
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From page 115... ...
Dry spot – An area of a reinforced plastic article that has (1) an insufficient amount of resin to wet out the reinforcement completely or (2)
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From page 116... ...
115 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual can be formed into yarn without twist or with very low twist. Used in filament winding processes and in filamentary composites that require long continuous strands.
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From page 117... ...
Laminate, angle-ply – Consists of an arbitrary number of layers identical in thickness and material and having alternating directions +x and −x. Laminate, cross-ply – Consists of an arbitrary number of layers of the same material and thickness but with alternating orientations of 0° and 90°.
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From page 118... ...
117 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual NDI – Nondestructive inspection. NDT – Nondestructive testing.
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From page 119... ...
Ultrasonic C-scan – A nondestructive inspection technique for composites in which a short pulse of ultrasonic energy is incident on a sample. Measurement of the transmitted pulse indicates the sample's attenuation of the incident pulse.
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From page 120... ...
119 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual INDEX A Acoustic emission, 57 Acoustic testing, 57 Approach joint, 36, 44, 85 Assessment guidelines, 92, 93 B Blistering, 46, 48, 53, 85, 112 Bolted connection, 35, 43 Brooming, 50 C Case study, 4, 30, 31, 32, 36, 39, 106 Cast-in-place connection, 34 Chain drag, 71 Checklists, standard, 85 Clip connection, 34, 42 Condition rating, 93 Cracking, 45, 46, 51, 52, 53, 54, 58, 59, 63, 65, 66, 67, 68, 72, 73, 76, 82, 83, 84, 91, 92, 93, 96, 98, 99, 100, 101, 103 Curbs, sidewalks, parapets, & railings, 36, 37, 38, 100 D Damage and defects, visual signs, 45, 46, 48, 49, 50, 51, 52, 53, 54, 58, 59, 63, 65, 66, 67, 68, 71, 72, 73, 76, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 96, 98, 99, 100, 101, 103, 112, 118 Damage, likely causes of, 51, 90, 101, 102, 103, 104 Darke County Bridge, 39
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From page 121... ...
Delamination, 45, 71, 76, 86, 88, 96 Discoloration, 49, 86, 101 E External details, inspection of, 44, 45, 67, 70, 81, 93, 101 F Facesheet, 46, 52 Fiber exposure, 50 Fiber reinforcement, 11 Foam core, 15 FRP, civil uses of, 7 FRP, constituent materials of, 7, 8, 11, 12, 13, 15, 16, 23, 24, 114, 115 FRP deck critical details, 32, 36, 39, 44, 46, 52, 64, 65, 85, 89, 90, 92, 98 FRP deck damage types, 39, 92, 93 FRP deck installation, 18, 26, 27, 36 FRP deck joint details, 27, 28, 29, 30, 31, 32, 34, 35, 41, 42, 43, 75 FRP deck manufacturing, 19, 20, 23, 24, 87 FRP deck types, 19, 20 FRP, material characteristics, 8 G Gelcoat, 16, 115 H Hand lay-up, 21, 22 Historic data, evaluation of, 83 Hollow core sandwich, 20 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 120
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From page 122... ...
121 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual Honeycomb sandwich, 19 I Impact, 51, 88, 90, 101 Inspection, frequency of, 81 Inspection types, 42, 43, 53, 54, 58, 59, 63, 80, 86, 87, 109, 118 Inspector qualifications, 64 Interference fit, 27, 43 Internal details, inspection of, 76 J Jay Street Bridge, 28, 29 Joints, 27, 31, 32, 36, 41, 44, 89, 93, 98 K King Stormwater Channel Bridge, 28, 34, 39 L Load-test method, 60, 61 M Matrix resin, 9 Modal analysis, 59, 60, 64 R Radiography, 59, 86, 87 Recordkeeping, 82, 83 Reflective cracking, 65, 66
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From page 123... ...
S Salem Avenue Bridge, 4, 30, 31, 32, 36, 39, 106 Schuyler Heim Bridge, 16, 17, 28, 29, 30, 35, 60, 78 Shear key, 28 Shear splice plate, 31, 41 Shear stud connection, 32, 42 Solid core sandwich, 19 T Tap testing, 42, 43, 54, 63, 71, 109 Thermal testing, 55, 56, 63 Thermography, 55, 56, 63 Tongue-and-groove, 27, 30 U Ultrasonic testing, 58, 63, 71, 76, 118 UV exposure, 103 V Vacuum-assisted resin-transfer molding, 19, 23 Visual inspection, 53, 63, 80 Voids, 118 W Wearing surface, 85, 89, 90, 92, 98 Wrinkling, 50 Field Inspection of In-Service FRP Bridge Decks: Inspection Manual 122
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Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.