In-Field Performance of the Modified Beam-in-Slab Bridge: A Replacement Option for Low-Volume Bridges

Managers of most low-volume roads (LVR) face a deteriorating bridge population, and replacement is frequently the most cost-effective solution. With more structures needing replacement than available funds to do so, low-cost alternatives that are constructible in-house are a desirable option. The modified beam-in-slab bridge (MBISB) is one such alternative that has been developed specifically for LVRs. The MBISB system consists of longitudinal steel stringers that support a transverse concrete arched deck. Composite action is obtained by using an alternative shear connector (ASC) rather than shear studs. Other than nominal transverse reinforcement, which is part of ASC, MBISB requires minimal additional reinforcement—approximately 70% of that required in conventional decks. Two demonstration bridges—MBISB 1, 50 ft (15.24 m) long and 31 ft (9.45 m) wide, and MBISB 2, 70 ft (21.34 m) long and 32 ft (9.75 m) wide-saved the bridge owner slightly more than 20% of the cost of conventional bridge systems. Field ...