Mud creek bridge foundation movements

摘要

A 400 ft (122 m) long, five-span concrete bridge over Mud Creek, supported on end bearing steel piles, was instrumented to measure horizontal movements of its foundations. Fifteen years of observations show that the abutments and piers have moved downslope and rocked back and forth through a small vertical angle about their bases. The net convergence of the abutments is about 4 cm. The horizontal movements were caused by soil creep in the marine clays of the steep valley slopes. The change in verticality of the piers was attributed to the expansion and the contraction of the bridge deck due to seasonal temperature variations. The steel end bearing batter piles were ineffective in maintaining the piers and abutments in their original positions.