Transporation agencies can reduce the costs and traffic impacts associated with placing soundwalls on bridges, which currently often requires rebuilding deck overhangs and exterior girders, while ensuring public safety in the event of vehicular impact. Currently, the only two soundwall systems approved for use on structures in California are cast-in-place concrete and masonry block. The masonry block wall is built almost exclusively on structures but is very heavy and therefore not cost effective. In order to crash test masonry block wall designs, research is needed to develop an impact criterion for soundwalls on structures that protects the traveling public from falling debris but is less cost prohibitive. In June 2003, an impact criterion for soundwalls on concrete barrier was developed that conservatively ensures that the TL 3 crash test using pickup trucks per the NCHRP Report 350 can be met. This made it possible for alternative systems to be approved by stamped calculations by a licensed engineer without crash testing for the TL 3 tests. The development of an impact criterion for TL 4 crash test is more complicated and requires testing to verify conformity similar to the European Norm EN1794-2. An impact criterion for soundwalls on structures would make the approval of alternative systems possible, meaning transportation agencies could build soundwall systems that are lighter and more cost effective. Since the majority of the cost in placing a soundwall on a bridge is in the bridge strengthening, the use of lightweight soundwall systems would reduce the cost of construction dramatically. The implementation of the lightweight soundwall systems would depend on industry to a large extent, but the magnitude of the approval process would be a fraction of what it is today.

Currently, in order for a soundwall system to be approved for use on structures, it must be tested at a TL 4 crash test per the NCHRP Report 350. The cost of this testing is in excess of $100,000 with no guarantee of successful results. A test method must be developed that envelopes the impact load from TL 4 crash tests as a substitute for vehicle destruction of large trucks and its associated expense. The test method results must then be compared to the TL 4 crash test results to prove that the test method is at least as stringent.

A test method must be developed that envelopes the impact load from at TL4 crash test without the destruction and associated expense. The test method results must be compared to the TL4 crash test results to prove that the test method is at least as stringent.

We anticipate a contribution of $25,000 per State or Partner spread over two years at $12,500 per year.