Proof Loading Test of Strengthened Reinforced Concrete Arch Bridge

Abstract

This paper presents the results obtained by the proof loading test performed on a strengthened reinforced concrete arch bridge over river Sushica on the road A3, section Kocani-Border with the Republic of Bulgaria on km. 272+649. The total length of the bridge is 102.8m, while the span of the arch is 74.82m. Static loading test was performed with four identical trucks applied in pre-defined positions. For the dynamic loading test, one truck, moving with different velocities, was used. Purpose of the loading test was to assess the quality of the strengthened bridge by comparing the real behaviour of the structure with the theoretical assumptions in the structural design. Deflections, as well as strains, were measured at several measurement points of characteristic cross sections. The measurement was performed by deflect meters and for some sections with survey equipment. Strains were measured with strain gauges for concrete and reinforcement and with data acquisition units DATALOG8. The measurement of the deflections for the dynamic loading test was performed by digital deflect meters. Estimation of the dynamic amplification factor (DAF) was the primary purpose of the dynamic loading test. Prior to the testing, structural finite element analysis of the bridge, using the actual loading test schemes, geometry and material data, was performed. This analysis defines the intensity of the gross-weight of the vehicles in order to obtain threshold values of internal forces and deflections within limits of 50 to 100% from the designed values. Analysis of the results shows good agreement between measured performance and numerically calculated values.