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It is estimated that there are more than half a million highway bridges in the United States. Many of these bridges have deteriorated considerably because of age and inadequate maintenance and inspections, whereas the average daily truck traffic and truck loads have increased. Careful evaluation is required to make rational economic and safety decisions concerning the rehabilitation of each bridge. Proof load testing is an efficient tool that can be used to evaluate the performance of existing bridges. The objective of the study was to ensure the safety of two highway bridges located in Michigan by proof load testing. For the first bridge the design details were not available, and the second bridge had heavy corrosion in the lower flanges of its steel girders. Usually, the proof load level is about twice the maximum allowable load. Allowable loads in Michigan are considerably higher than those in other states. Therefore, military tanks on flatbed trailers were used to achieve the high target proof load levels. These tanks were provided by the Michigan National Guard. Load was increased in several steps, and the strains and deflections in the girders were measured. No sign of distress was observed during the tests. The capacity of each bridge was found to be significantly higher than the analytical capacity.

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Roads and BridgesINTRODUCTION Bridges in the Kachchh region are generally stream or railway crossings. The affected area has significant road and rail networks. There are several major highway and railway bridges, and many small to medium bridges. As per Roads and Buildings (R&B) Department of the Government of Gujarat, 900 km of roadways and over 500 bridges were damaged in the January 26, 2001 earthquake.Bridges in the area are typically composed of short spans with span lengths of approximately 15 m. Bridges are simple spans with expansion joints at each pier and supported on elastomeric bearings with no continuity of the superstructure or any fixity at the intermediate diaphragms. Lshaped abutments are typical for all newer concrete and older masonry bridges. The substructure of most bridges is wall piers supported on shallow foundations with no consideration for ductility. Use of deep foundations is not prevalent, even though liquefaction and lateral spreading is to be expected in the region in a seismic event.Both existing bridges and those under construction suffered extensive damage during the earthquake (Jain et al., 2001).Precast concrete members are occasionally used in the construction of bridges. Precast/ prestressed concrete bridges performed better, relatively, than cast-in-place concrete or other types of bridges. The better performance of the precast/prestressed bridges can be attributed to the higher quality of construction in the fabrication of precast members.The State Highway system suffered damage primarily to road surfaces, while the National Highway system's main damage was to bridge structures. A summary of damages sustained by the roads and bridges along State Highway and National Highway in the affected area is presented in Tables 19-1 and 19-2. ROADSThe road system consists of National Highways, State Highways, Major District Roads, Other District Roads, and Village Roads. In the affected area, there are over 5400 km of roadways. Worst affected was the Kachchh district itself. Types of damages sustained include:9Longitudinal cracks along the central carriageway and shoulders of elevated road embankments. 9 Transverse cracks between the bridge spans and the roadway. 9 Longitudinal/transverse cracks along ground fissure lines crossing the road system. 9 Settlement/uplift of road at some locations. The Gujarat Roads and Buildings Department administers the design, construction, and maintenance of roadways, bridges, and other structures in the State of Gujarat. National Highway 8 (NH8) is the most important road in the Kachchh region. NH8A connects local ports and towns to India's