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From page 375... ... 375 CHAPTER 14 – EFFECTS OF W-BEAM SPLICE DAMAGE ON RAIL CAPACITY The effects of crash-induced damage on the residual capacity of w-beam splices were evaluated using physical impact testing. In Report 656 a single damage mode was evaluated for the w-beam splice, which involved a "cut out" of w-beam material around the lower upstream splice bolt. Read the entire page →
From page 376... ... 376 Procurement and Assessment of Damaged W-Beam Splices A total of fifteen damaged splice samples were provided to the study by the Maine Department of Transportation (MEDOT) ; however, a number of those did not have sufficient damage for consideration in the test program. Read the entire page →
From page 377... ... 377 2. Rail Separation – Two types of rail separation were measured: a. Read the entire page →
From page 378... ... 378 Figure 325. Rail flattening – Rail flattening and rail crush at each quadrant of the splice is measured from the center of the w-beam to the top/bottom edge at the splice bolts. Read the entire page →
From page 379... ... 379 Figure 327. Rail separation – Longitudinal slip in splice connection. Read the entire page →
From page 380... ... 380 Figure 329. Splice bolt hole stretching – Stretching of the splice bolt hole is evidenced in this photo by the apparent longitudinal movement of the splice bolt relative to its original position. Read the entire page →
From page 381... ... 381 Figure 331. Horizontal and vertical tears – tears were measured and categorized according to location on upstream and downstream panel as denoted here. Read the entire page →
From page 382... ... 382 Table 81. Summary of "rail flattening" damage mode for MEDOT crash-damaged splice specimens – listed in descending order, w.r.t maximum degree of flattening. Read the entire page →
From page 383... ... 383 Table 82. Summary of "rail crush" damage mode for MEDOT crash-damaged splice specimens – listed in descending order, w.r.t maximum degree of crush. Read the entire page →
From page 384... ... 384 Table 83. Summary of "rail separation" damage mode for MEDOT crash-damaged splice specimens – listed in descending order, w.r.t maximum separation. Read the entire page →
From page 385... ... 385 Table 84. Summary of "visible splice bolt and splice bolt hole" damage mode for MEDOT crash-damaged splice specimens. Read the entire page →
From page 386... ... 386 Table 85. Summary of "non-bolt-hole tear" damage mode for MEDOT crash-damaged splice specimens – listed in descending order w.r.t maximum vertical tear, then maximum horizontal tear. Read the entire page →
From page 387... ... 387 Inspection of Unassembled Splice (for Hidden Damages in the Splice-Holes) The next step of the research approach involved disassembly of the damaged splice samples in order to assess damages to the splice-bolt holes. Read the entire page →
From page 388... ... 388 Accelerometers The pendulum was instrumented with three accelerometers mounted onto the backside of the pendulum mass. Accelerometers 1 and 3 recorded data in the x-direction (forward direction) Read the entire page →
From page 389... ... 389 Figure 334. High-speed camera specifications and placement. Read the entire page →
From page 390... ... 390 Figure 335. Sequential views of a pendulum test performed in Gabler's study. Read the entire page →
From page 392... ... 392 Figure 338. Anchoring of the downstream end of the rail for Test Series 14004. Read the entire page →
From page 393... ... 393 Impact Conditions The 4,360-lb pendulum struck the w-beam rail at 37.5 inches upstream of the splice connection. The nominal impact speed was 20.5 mph, which resulted in 734 kip-in of kinetic energy for the striker. Read the entire page →
From page 394... ... 394 Table 86. Pendulum test matrix for the splice damage study. Read the entire page →
From page 395... ... 395 Results A summary of the test results for Test Series 14004 are shown in Table 87, including damage mode case, damage level, impact velocity, failure mode, peak force during the impact, and the maximum energy absorbed by the guardrail system up to the point of rail rupture. The resulting peak impact force and peak energy for each case is also shown graphically in Figures 341 and 342. Read the entire page →
From page 396... ... 396 Figure 341. Peak impact force for each damage mode case investigated in test series 14004F-O. Read the entire page →
From page 397... ... 397 Figure 343. Read the entire page →
From page 398... ... 398 Figure 344. Read the entire page →
From page 399... ... 399 Figure 345. Read the entire page →
From page 400... ... 400 Figure 346. Read the entire page →
From page 401... ... 401 Figure 347. Sequential views of Tests 14004F and 14004G. Read the entire page →
From page 402... ... 402 Figure 348. Sequential views of Tests 14004H and 14004I. Read the entire page →
From page 403... ... 403 Figure 349. Sequential views of Tests 14004J and 14004K. Read the entire page →
From page 404... ... 404 Figure 350. Sequential views of Tests 14004L and 14004M. Read the entire page →
From page 405... ... 405 Figure 351. Sequential views of Tests 14004N and 14004O. Read the entire page →
From page 406... ... 406 Discussion of Test Results Pendulum impact tests were performed to evaluate the effects of crash-damage on the capacity of w-beam rail splices. For standard strong-post guardrail systems, such as the modified G4(1S) Read the entire page →
From page 407... ... 407 section of the rail splice. The force and energy curves shown in Figure 343 indicate that this test article resulted in essentially the same capacity as the undamaged test article in Test 14004O. Read the entire page →
From page 408... ... 408 horizontal tear downstream of the splice connection. Since the horizontal tear was located downstream of the splice connection, its effect was considered negligible in the test. Read the entire page →
From page 409... ... 409 (gap) between the two rail elements at the downstream edge of the splice. Read the entire page →
From page 410... ... 410 Table 88. Recommendations for assessment criteria for w-beam splice damage. Read the entire page →

From page 375...

... 375 CHAPTER 14 – EFFECTS OF W-BEAM SPLICE DAMAGE ON RAIL CAPACITY The effects of crash-induced damage on the residual capacity of w-beam splices were evaluated using physical impact testing. In Report 656 a single damage mode was evaluated for the w-beam splice, which involved a "cut out" of w-beam material around the lower upstream splice bolt.