I-276 Delaware River-Turnpike Toll Bridge had which failure observed?

I-276 Delaware River-Turnpike Toll Bridge had which failure observed?

• A. T1 steel butt weld failure
• B. Impact damage
• C. Overloaded gusset plates
• D. Rivet hole filled with wellment started a crack

Answer: (D)

Fatigue cracking in steel bridges often starts at stress risers created by small changes in geometry or metallurgy, such as a rivet hole or a repaired area. When a rivet hole is later filled with weld metal, the weld introduces a heat-affected zone and residual stresses around the hole. This combination creates a sharp notch at the weld-to-steel interface, making it a prime site for crack initiation under the repeated loading of traffic. On the I-276 Delaware River–Turnpike Toll Bridge, inspectors observed a crack that began at a rivet hole filled with weldment, which fits this fatigue-prone scenario. Other failure modes—like a standalone butt weld failure, a single impact event, or overstressed gusset plates—would show different origins or evidence and are not the observed crack initiation point in this case.

Fatigue cracking in steel bridges often starts at stress risers created by small changes in geometry or metallurgy, such as a rivet hole or a repaired area. When a rivet hole is later filled with weld metal, the weld introduces a heat-affected zone and residual stresses around the hole. This combination creates a sharp notch at the weld-to-steel interface, making it a prime site for crack initiation under the repeated loading of traffic. On the I-276 Delaware River–Turnpike Toll Bridge, inspectors observed a crack that began at a rivet hole filled with weldment, which fits this fatigue-prone scenario. Other failure modes—like a standalone butt weld failure, a single impact event, or overstressed gusset plates—would show different origins or evidence and are not the observed crack initiation point in this case.