The use of precast, prestressed concrete piles in the foundation of bridge piers has long been recognized as a valuable option for bridge owners and designers. However, the use of these precast, prestressed concrete piles in integral abutment bridges has not been widespread because of concerns over pile flexibility and the potential for concrete cracking and deterioration of the prestressing strands due to long-term exposure to moisture. This report presents the details of the first integral abutment bridge in the state of Iowa that utilized precast, prestressed concrete piles in the abutment. The bridge, which was constructed in Tama County in 2000, consists of a 110 ft long, 30 ft wide, single-span PC girder superstructure with a left-side-ahead 20o skew angle. The bridge was instrumented with a variety of strain gages, displacement sensors, and thermocouples to monitor and help in the assessment of structural behavior. The results of this monitoring are presented, and recommendations are made for future application of precast, prestressed concrete piles in integral abutment bridges. In addition to the structural monitoring data, this report presents the results of a survey questionnaire that had been mailed to each of the 50 state DOT chief bridge engineers to ascertain their current practices for precast, prestressed concrete piles and especially the application of these piles in integral abutment bridges.

This CD-ROM accompanies NCHRP Report 527, Steel Box-Beam Pier Caps. It contains the following appendixes: (A) Questionnaire on Past Use of Integral Pier Caps; (B) Literature Review; (C) Integral Pier Concepts; (D) Prototype Bridge Configuration, Loading and General Experimental Configuration; (E) Test Fixture and Loading System; (F) Design, Construction, Testing and Results from Specimen SPC1; (G) Design, Construction, Testing and Results from Specimen SPC2; and (H) Proposed Design Specifications Articles and Commentary.

An analytical study was conducted to assess the effectiveness of different types of intermediate diaphragms in reducing the damage to the girders of a pre-stress girder (PC) bridge that is struck by an over-height object on a highway vehicle. Finite-element models were developed for non-skewed and skewed, PC girder bridges with three different diaphragm types. The bridge models were analyzed for a lateral-impact load that was applied to the bottom flange of the exterior girders at the intermediate diaphragm location and away from the diaphragm location. The induced strains and displacements in the girders were established for the different diaphragms. When a lateral-impact load was applied at the diaphragm location, the reinforced concrete, intermediate diaphragm provided more protection for the girders than that provided by the two types of structural steel, intermediate diaphragms, on the other hand, the different diaphragm types provided essentially the same degree of impact protection for the PC girders when the load was applied away from the diaphragm location.

This paper presents an overview of a research project that investigates integral concrete pier and steel girder bridge systems for seismic regions. The major aspects of this research are to design an integral connection for a two-span, prototype bridge that consists of a single column bent, steel girders and a steel cap beam; to perform experimental verification of the connection details; and to establish the overall seismic performance of the bridge system. Two test units at 1/3-scale were planned for the experimental component of this study. Testing of the first unit has recently been completed, which exhibited satisfactory seismic performance by developing the plastic moment capacity in the column, as intended in the design. The superstructure response was elastic, confirming the adequacy of the girder-to-cap and column-to-cap connection details. The design approach, connection details, observed behavior, and preliminary test results for the first test unit are also included in the paper.

In 1957, the Iowa State Highway Commission, with financial assistance from the aluminum industry, constructed a 220-ft (67-m) long, four-span continuous, aluminum girder bridge to carry traffic on Clive Road (86th Street) over Interstate 80 near Des Moines, Iowa. The bridge had four, welded I-shape girders that were fabricated in pairs with welded diaphragms between an exterior and an interior girder. The interior diaphragms between the girder pairs were bolted to girder brackets. A composite, reinforced concrete deck served as the roadway surface. The bridge, which had performed successfully for about 35 years of service, was removed in the fall of 1993 to make way for an interchange at the same location. Prior to the bridge demolition, load tests were conducted to monitor girder and diaphragm bending strains and deflections in the northern end span. Fatigue testing of the aluminum girders that were removed from the end spans were conducted by applying constant-amplitude, cyclic loads. These tests established the fatigue strength of an existing, welded, flange-splice detail and added, welded, flange-cover plates and horizontal web plate attachment details. This part, Part 2, of the final report focuses on the fatigue tests of the aluminum girder sections that were removed from the bridge and on the analysis of the experimental data to establish the fatigue strength of full-size specimens. Seventeen fatigue fractures that were classified as Category E weld details developed in the seven girder test specimens. Linear regression analyses of the fatigue test results established both nominal and experimental stress-range versus load cycle relationships (SN curves) for the fatigue strength of fillet-welded connections. The nominal strength SN curve obtained by this research essentially matched the SN curve for Category E aluminum weldments given in the AASHTO LRFD specifications. All of the Category E fatigue fractures that developed in the girder test specimens satisfied the allowable SN relationship specified by the fatigue provisions of the Aluminum Association. The lower-bound strength line that was set at two standard deviations below the least squares regression line through the fatigue fracture data points related well with the Aluminum Association SN curve. The results from the experimental tests of this research have provided additional information regarding behavioral characteristics of full-size, aluminum members and have confirmed that aluminum has the strength properties needed for highway bridge girders.

The main objectives of the research reported in this paper were to investigate the effectiveness of intermediate RC and steel diaphragms in PC, girder-slab bridges that are subjected to lateral load and to determine whether steel diaphragms of some conventional configuration are essentially structurally equivalent to cast-in-place RC diaphragms. The investigation included analytical studies and testing of a full-scale-model, PC, girder-slab bridge.

Aluminum bridge structures are unique structures. They have been used as a viable alternative during periods when fabricated structural steel has been difficult to obtain. However, in recent years, there has been increased interest in new bridge materials, including aluminum. Its lightweight and corrosion resistance provides opportunities for its use in special situations. Additional research that addresses the behavior of full-scale aluminum members needs to be conducted to provide behavioral characteristics that can be incorporated into additional design recommendations for aluminum bridge structures and components.In 1957 the Iowa State Highway Commission, with financial assistance from the aluminum industry, constructed a 67 m (220 ft) long, four-span continuous, aluminum girder bridge to carry traffic on Clive Road (86th Street) over Interstate 80 near Des Moines, Iowa. The bridge, which was one of only nine existing aluminum girder bridges in the continental United States, was constructed with four, all-welded, aluminum girders. The girders were fabricated in pairs with welded diaphragms between the girders. The interior diaphragms between the girder pairs were bolted to girder brackets. A composite, reinforced concrete (RC) deck served as the roadway surface. The bridge, which had performed successfully for about 35 years, was removed in the fall of 1993 to make way for an interchange at the same location. The bridge demolition provided a unique opportunity to load test the bridge prior to its removal and to obtain some of the aluminum girders for fatigue testing.Load tests of the bridge were conducted by driving an overloaded truck to preselected locations on the bridge deck and then monitoring the induced strains in the girder flanges and diaphragm webs of the bridge, Deflections were also measured. Fatigue testing of the aluminum girders that were removed from the end spans were conducted by applying constant-amplitude, cyclic loads. These tests established the fatigue strength of an existing, welded, flange-splice detail and added, welded, flange, cover plates and web-stiffener plate details. The results from the experimental tests of this research will provide additional information regarding behavioral characteristics of full-scale, aluminum members and confirm that aluminum has the strength properties needed for highway bridge girders. This paper will focus on the analysis of the experimental data to establish the behavior of the aluminum girder bridge and aluminum girders.

Each year several prestressed concrete girder bridges in Iowa and other states are struck and damaged by vehicles with loads too high to pass under the bridge. Whether or not intermediate diaphragms play a significant role in reducing the effect of these unusual loading conditions has often been a topic of discussion. A study of the effects of the type and location of intermediate diaphragms in prestressd concrete girder bridges when the bridge girder flanges were subjected to various levels of vertical and horizontal loading was undertaken. The purpose of the research was to determine whether steel diaphragms of any conventional configuration can provide adequate protection to minimize the damage to prestressed concrete girders caused by lateral loads, similar to the protection provided by the reinforced concrete intermediate diaphragms presently being used by the Iowa Department of Transportation. The research program conducted and described in this report included the following: A comprehensive literature search and survey questionnaire were undertaken to define the state-of-the-art of intermediate diaphragms in prestressed concrete girder bridges. A full scale, simple span, prestressed concrete girder bridge model, containing three beams was constructed and tested with several types of intermediate diaphragms located at the one-third points of the span or at the mid-span. Analytical studies involving a three-dimensional finite element analysis model were used to provide additional information on the behavior of the experimental bridge. The performance of the bridge with no intermediate diaphragms was quite different than that with intermediate diaphragms in place. All intermediate diaphragms tested had some effect in distributing the loads to the slab and other girders, although some diaphragm types performed better than others. The research conducted has indicated that the replacement of the reinforced concrete intermediate diaphragms currently being used in Iowa with structural steel diaphragms may be possible.