TTI Research Supervisor:
Akram Abu-Odeh, Ph.D.
Texas Transportation Institute
Texas A&M University System
College Station, Texas 77843-3135
(979) 862-3379 [email protected]
Pooled Fund Technical Representative:
Standards and Criteria Engineer
Pennsylvania Department of Transportation
400 North Street
Harrisburg, PA 17105
(717) 783-5110 [email protected]
The purpose of the Crash Wall Design study was to evaluate impact response of a crash wall design installed in front of mechanically stabilized earth (MSE) walls. The evaluation method utilized two combined finite element models: a typical MSE wall structure and a crash wall component. Anchors models were used to tie the crash wall to the panels of the MSE wall. Initial stresses in the reinforcing strips were determined using initialization simulation and verified using American Association of State Highway and Transportation Officials (AASHTO) formulae.
A simulation of 10,000 kg Single Unit Truck (SUT) traveling at a speed of 90 km/h (56 mph) and impacting the crash wall at an angle of 15 degrees was used to represent the errant impact load.
Figure 1. Typical Crash Wall Section from PennDOT Drawing.
(a) FE Model of a Typical MSE Wall
(b) FE Model of an MSE Wall with a Crash Wall
Figure 2. Set-up of MSE Wall Models.
Simulations showed damage to wall panels from the direct impact of the SUT, meaning that wall panels would not sufficiently resist direct impact by a heavy truck with high impact severity. However, when a 0.2 m (8-inch) thick crash wall is placed in front of panels, the panels exhibit minor damages.
Direct impact to wall panels often results in complicated, expensive repairs to the MSE wall system. However, reconstructing a crash wall is much more feasible as it requires pouring concrete and can therefore be achieved efficiently and it is much more economically feasible than replacing MSE wall panels.