This paper presents design recommendations of non-composite reinforced concrete bridge decks subjected to fatigue due to moving loads. These recommendations are based on test results of 1/3- and 1/6.6- scale physical models of a full-scale 21.6-cm (8.5 in.) thick and 15.24-m (50-ft) long simply supported non-composite reinforced concrete deck. Concrete bridge decks should be designed to transfer the load in a two-way action. Experimental results show that the two-way slab action in the decks changes to a one-way action (transverse direction) as fatigue damage due to a moving wheel-load accumulates. It is recommended to adopt an isotropic steel reinforcing pattern. An isotropic reinforcing pattern with a steel ratio of 0.3 % (each top and bottom layer) in each direction appears to be adequate. A similar reinforcing amount and pattern is required by the Ontario bridge design Code. The required steel content is therefore reduced resulting in substantial savings in the bridge deck construction costs and improving the corrosion resistance in decks, especially in the presence of deicing chemicals. It appears that flexural cracking in the deck and bond failure at the steel-concrete interface are necessary and sufficient conditions for deck failure under traffic loads. It is, thus, highly desirable to preclude or at least limit cracking and maximize the bond strength of the steel rebars.

Contains papers from a May 1997 symposium held in St. Louis, addressing different aspects of product quality as it relates to structural integrity, and the influence of design criteria on structural integrity. Topics include low-cycle fatigue testing of tubular material using non-standard specimens,

This research evaluated the feasibility of the empirical design method for reinforced concrete bridge decks for the Florida Department of Transportation [FDOT]. There are currently three methods used for deck design: empirical method, traditional method and finite element method. This research investigated and compared the steel reinforcement ratios and the stress developed in the reinforcing steel for the three different methods of deck design. This study included analysis of 15 bridge models that met the FDOT standards. The main beams were designed and load rated using commercial software to obtain live load deflections. The bridges were checked to verify that they met the empirical method conditions based on the FDOT Structures Design Guidelines-- January 2009. The reinforced concrete decks were designed using the traditional design method. Then the bridges were analyzed using three-dimensional linear finite element models with moving live loads. The reinforced concrete decks were designed using dead load moment, live load moment, and future wearing surface moment obtained from the finite element models. The required reinforcing steel ratio obtained from the finite element method was compared to the required reinforcing steel ratio obtained from traditional design method and the empirical design method. Based on the type of beams, deck thicknesses, method of analysis, and other assumptions used in this study, in most cases the required reinforcing steel obtained from the finite element design is closer to that obtained from the empirical design method than that obtained from the traditional design method. It is recommended that the reinforcing steel ratio obtained from the empirical design method be used with increased deck thicknesses to control cracking in the bridge decks interior bays.

One of the major tasks of an on-going research project is to improve the current AASHTO design approach of reinforced concrete bridge deck slabs. Tests are conducted on non-composite reinforced concrete bridge deck models supported on steel girders to study the failure mechanisms under static, fixed pulsating and moving wheel-loads. This paper presents the test results of two 1/6.6 (B-series) bridge deck models of an 8.5 in. thick and 50 ft. long prototype concrete bridge deck supported on four simply supported steel girders spaced at 10 ft. and subjected to a static concentrated wheel-load. The effect of lateral restraint and amount of reinforcement (Ontario vs. AASHTO design) on the arching action mechanism and the load-deflection response of the bridge model decks is determined and discussed. Tests are also reported on 1/6.6 (B-series) and 1/3 scale (P-series) deck panels simply supported between two adjacent steel girders to evaluate any size effects on the static ultimate strength of the B-series deck models. In addition to the load-deflection curves, cracking pattern, failure mode and a comparison between the observed ultimate strength values and those predicted by the yield-line theory and ACI code are presented. Strains are measured in the reinforcing bars and on the concrete surface; membrane compressive forces in the decks have been estimated but are not included in this paper. For the covering abstract of the Conference see IRRD Abstract No. 807839.