Book Description

The existing Montana Department of Transportation (DOT) concrete median barrier sections are 3.048 m (10 ft) long New Jersey shaped barriers with a pin-and-loop connection. Two pairs of 25 mm (1 in.) diameter wire rope loops are connected using a 660 mm (26 in.) long, 25 mm (1 in.) diameter pin that is not restrained at the bottom. Since the system has a low probability of complying with the NCHRP Report 350 guidelines, and the expected dynamic barrier deflection under design impact conditions is greater than desired by Montana DOT, two alternate barrier connection concepts were proposed and evaluated using computer simulations. These included a modified pin-and-loop connection and a newly conceived lapped splice connection. After these two designs appeared to perform acceptably during simulation, the proposed designs were constructed for full-scale crash testing to determine whether the designs would actually meet NCHRP Report 350 crash test criteria. This report presents the details of the simulation analysis, the details of the proposed barrier designs, the details of the full-scale crash tests, and the NCHRP Report 350 evaluation of each of the tests. Both the modified pin-and-loop barrier and the lapped splice connection barrier performed acceptably for NCHRP Report 350 test 3-11.