Shigeyuki Matsui

Trends in steel-concrete composite bridges in Japan

This paper presents trends in new types of steel-concrete composite bridge decks and piers in Japan, and focuses mainly on composite girders, slabs, and columns. Since 1953, many simple supported composite bridges were built in Japan, but this type of bridge has been built less often during the last two decades. Continuous composite girder bridges show a similar tendency. All continuous bridges constructed since 1973 have been non-prestressed. To increase the durability and load-carrying capacity of bridge slabs, and shorten construction times, various types of slabs for composite girders have been developed, mainly for simple span bridges. Composite girder bridges, using prestressed precast concrete slabs, have been developed recently in Japan. Other types of composite girder bridges include those with a corrugated steel web plate and external cables. The use of steel-concrete composite decks is likely to increase, due to the rapid deterioration of ordinary reinforced concrete slabs for highway bridges. Composite decks in Japan are generally partially precast, and are mainly steel plate-concrete slab composite or concrete-filled steel grillage composite. Applicable bridge types for composite columns are discussed briefly, and the mathematical theory of their strength and ductility is outlined.

Slab Behavior and Approximation of Transverse Strain Increase Due to the Change of Support Conditions from Rigid to Elastic Supports

When existing multiple simple span bridges are converted into a continuous span in order to increase the load carrying capacity by connecting each opposite ends of the simple beams, the rigid support conditions (pin and roller supports) have to be changed to elastic supports in order to absorb and distribute the energy of large horizontal motion due to earthquake loading. However, it may overlook the development of additional stress in the transverse direction of the slab due to the relative vertical displacement of the elastic support. In this study, a simple span bridge specimen of 1/6 scale is tested and analyzed by the use of F.E.M. to investigate strain increase in the transverse direction of the slab when the rigid supports are replaced by the elastic supports. Both test and analytical results exhibit a notable increase of transverse stress throughout the whole feasible range of the vertical support stiffness.

Evaluating Fatigue Resistance of FRP-Strengthened RC Bridge Decks Subjected to Repeated Wheel Load

One of the major causes of road infrastructure failure is traffic-induced fatigue of bridge superstructures, in particular concrete bridge deck panels Deterioration of steel reinforced concrete (RC) bridge decks a result of aging and fatigue is on the rise in many developed countries including Japan. This paper presents experimental work done in investigating traffic-induced fatigue mechanism of a normal RC bridge deck and the strengthening by fiber-reinforced polymer (FRP) sheets to extend fatigue life. Discussion is focused on experimental observations and development of a stress-passage (S-N) relationship that provides estimation to the fatigue life of deck as a result of FRP strengthening. Within the scope of study, the strengthening by FRP has proven to be a viable and relatively simple solution in salvaging RC bridge decks suffering from moderate level of fatigue damage, with fatigue life up to 28 times longer than that without strengthening.