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From page 417... ... 415 9.1 introduction Bridge elements are subjected to various loads, including traffic and environmental loads that result in movement of the bridge elements. One of the key factors affecting the service life of bridges is how to address thermal expansion and contraction of the bridge elements. Read the entire page →
From page 418... ... 416 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Section 9.2 describes the different types of expansion devices used in practice, as well as their various advantages and disadvantages. Section 9.3 discusses reported potential factors that could affect the service life of the different expansion devices, and Section 9.4 provides strategies for enhancing expansion device service life. Read the entire page →
From page 419... ... 417 Chapter 9. ExpANSiON DEviCES 9.2.1 Expansion Joints with Small movement Capabilities 9.2.1.1 Compression Seal Joints In an expansion joint that uses a compression seal, the opening throughout the entire bridge-deck width is filled with a neoprene elastomeric section that forms a waterproof joint, as shown in Figure 9.1 (Purvis 2003) Read the entire page →
From page 420... ... 418 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE • The compression seal fits into the sides of the joint by using a lubricant material that also functions as an adhesive that bonds the seal to its place. • Splices should be avoided in this type of seal. Read the entire page →
From page 421... ... 419 Chapter 9. ExpANSiON DEviCES Figure 9.2. Read the entire page →
From page 422... ... 420 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 9.2.1.2.4 Requirements • The thickness of the silicone at the center should be no more than half the width of the joint. • It is important that the bottom of the silicone does not bond to the material below. Read the entire page →
From page 423... ... 421 Chapter 9. ExpANSiON DEviCES Figure 9.3. Read the entire page →
From page 424... ... 422 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 9.2.1.5 Sliding Plate Joints Figure 9.5 shows a typical sliding plate joint. According to some literature (Purvis 2003) Read the entire page →
From page 425... ... 423 Chapter 9. ExpANSiON DEviCES • Damage accumulated at the unsupported edge of the sliding plate causes a weak spot for traffic-impact loads. Read the entire page →
From page 426... ... 424 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Figure 9.7. Strip seal expansion joint. Read the entire page →
From page 427... ... 425 Chapter 9. ExpANSiON DEviCES movements. Read the entire page →
From page 428... ... 426 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE • They can be sized according to the magnitude of movement and have been designed to accommodate movements of more than 7 ft (very long span) Read the entire page →
From page 429... ... 427 Chapter 9. ExpANSiON DEviCES 9.2.3.2.1 Features • The system consists of finger-like plates attached to both sides of the super structure and usually includes a drainage trough. Read the entire page →
From page 430... ... 428 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 9.2.3.2.4 Requirements • Watertightness and good drainage are important considerations for finger-plate expansion joints. Use of appropriate slope (minimum 1%) Read the entire page →
From page 431... ... 429 Chapter 9. ExpANSiON DEviCES 9.3.1.1.1 Fatigue Fatigue is caused by the repetition of applied loads that result in a degradation of the strength resistance of the components used to resist tensile stresses that occur in expansion devices (especially in modular expansion joints and other large-movement joints) Read the entire page →
From page 432... ... 430 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Figure 9.11. Load-induced deficiency fault tree. Read the entire page →
From page 433... ... 431 Chapter 9. ExpANSiON DEviCES 9.3.1.2 System-Dependent Loads System-induced loads include the effects of the bridge system configuration on the behavior of the bridge-deck expansion devices. Read the entire page →
From page 434... ... 432 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Figure 9.12. Natural or man-made hazards fault tree. Read the entire page →
From page 435... ... 433 Chapter 9. ExpANSiON DEviCES 9.3.2.2 Coastal Climate Coastal climate influences on bridge expansion joint service life performance are primarily due to chlorides introduced through salt spray and effects from high humidity. Read the entire page →
From page 436... ... 434 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Figure 9.13. Production–operation and design–detailing defects fault tree. Read the entire page →
From page 437... ... 435 Chapter 9. ExpANSiON DEviCES interval of these inspections should be calibrated on the basis of bridge expansion device performance history for the applicable deck hazard exposures. Read the entire page →
From page 438... ... 436 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 9.4.4 Construction Practice Specifications Once the bridge expansion joint system is selected, a proper set of specifications must be developed to ensure the appropriate standard of care is used during construction. It should be noted that many agencies and manufacturers have specific requirements for temperature setting for expansion joints to allow maximum range of movements; these requirements need to be considered during design and construction. Read the entire page →
From page 439... ... 437 Chapter 9. Read the entire page →
From page 440... ... 438 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE tAbLe 9.1. bridge jointS technoLogy tAbLeS (continued) Read the entire page →
From page 441... ... 439 Chapter 9. Read the entire page →
From page 442... ... 440 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE tAbLe 9.1. bridge jointS technoLogy tAbLeS (continued) Read the entire page →
From page 443... ... 441 Chapter 9. Read the entire page →
From page 444... ... 442 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE tAbLe 9.1. bridge jointS technoLogy tAbLeS (continued) Read the entire page →
From page 445... ... 443 Chapter 9. ExpANSiON DEviCES 9.4.8 Strategy table for Expansion Joints Selecting the appropriate expansion device for the required movement range is the most critical step in enhancing the service the life of these joints. Read the entire page →
From page 446... ... 444 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE tA B LE 9 .2 . Read the entire page →

From page 417...

... 415 9.1 introduction Bridge elements are subjected to various loads, including traffic and environmental loads that result in movement of the bridge elements. One of the key factors affecting the service life of bridges is how to address thermal expansion and contraction of the bridge elements.