Journal of Bridge Engineering

The objective of this paper is to provide highlights of the most important references related to the development of current guide specifications for the design of straight and curved box-girder bridges. Subjects discussed in this review include (1) different box-girder bridge configurations; (2) construction issues; (3) deck design; (4) load distribution; (5) deflection and camber; (6) cross-bracing requirements; (7) end diaphragms; (8) thermal effects; (9) vibration characteristics; (10) impact factors; (11) seismic response; (12) ultimate load-carrying capacity; (13) buckling of individual components forming the box cross section; (14) fatigue; and (15) curvature limitations provided by the codes for treating a curved bridge as a straight one. The literature survey presented herein encompasses (1) the construction phase; (2) load distribution; (3) dynamic response; and (4) ultimate load response of box-girder bridges.

Active vibration control of long span suspension bridge flutter using separate control flaps (SFSC) has shown to increase effectively the critical wind speed of the bridges. In this paper, an SFSC calculation based on modal equations of the vertical and torsional motions of the bridge girder including the flaps is presented. The length of the flaps attached to the girder, the flap configuration, and the flap rotational angles are parameters used to increase the critical wind speed of the bridge. To illustrate the theory a numerical example is shown for a suspension bridge of 1,000 + 2,500 + 1,000 m span based on the Great Belt Bridge streamlined girder.

A parallel wire strand (PWS) rope instead of a strand rope of the center fit rope core type was used as the hanger rope in the world's longest suspension bridge, the Akashi Kaikyo Bridge, one of the Honshu-Shikoku Bridges in Japan. The strand ropes of the center fit rope core type are inconvenient and uneconomical to maintain as 100–200 m-long hanger ropes. This paper presents the design method for the PWS hanger system in long-span suspension bridges. The structural characteristics, structural analysis, stress calculation, and the examination of fatigue against random wind load of the PWS hanger system were also investigated.

This paper presents the results of mock-up cable erection tests for the Yong Jong Grand Bridge, Inchon, Korea. The Grand Bridge includes the world's first self-anchored spatial suspension bridge whose main cable planes are inclined in the transverse direction. Cable erection problems were expected to occur at the pylon saddle and the splay band due to the self-anchored cable system and the difference between the erection and completed layout of the main cable. The mock-up tests were performed prior to actual cable erection. Through the tests, cable erection problems at the saddle, lateral displacement, and bending of the wires inside the saddle were identified, and measures to deal with the problems were devised and tested. The tested measures were successfully implemented for the construction of the bridge.

This paper presents an evaluation of the seismic performance and retrofit of reinforced-concrete bridge columns with structural flares. Experimental and analytical studies were performed on four 40%-scale specimens. Two specimens represented the as-built columns, while the other two were retrofitted with steel jackets for shear capacity enhancement. The results indicate that some of the existing methods for evaluating the shear capacity of columns can be unconservative and could overestimate the shear capacity of the columns included in this study by 60%. It is also shown that by implementing proper detailing, steel jackets can be used to enhance the shear capacity and ductility of flared columns with no appreciable increase in the shear demand.

Out-of-plane stresses due to the wedging effect of the strands caused high stress concentration at the end of the transition zone of Florida bulbtee girders. Adding the hydrostatic stresses due to grout pressure in the posttensioning ducts severed the tensile stresses in the web section and caused some crack initiation between the ducts and on the surface of the girders. Other related factors were found to contribute to these stresses. Among these factors were the shape of the posttensioning ducts, and the type of the duct material. Two fully instrumented 22.9-m-long Florida bulbtee end girders were prepared and tested under typical field conditions. Testing results indicated that stress accumulation due to the grout pressure was more severe in ducts with oval cross sections than in the round ones. Although steel ducts were used in the full-scale field testing, a comparative study using 3D nonlinear finite-element analyses showed that cracking was even more severe when using high-density polyethylene ducts.

A computer-based, graphical approach is presented to construct the Influence Profile for determinate bridge structures that are subjected to multiple axle loads. An Influence Profile represents the variation of an internal or external force, or moment, at a specific location of a structure, under loading by an actual vehicle (e.g., AASHTO HS-20 truck, American Railway Engineering and Maintenance-of-Way Association (AREMA) Cooper E-80 train). The technique works by scaling the influence line ordinates by the individual axle weights of the vehicle, and by applying distance delays to account for the horizontal separation between axles. The scaled and shifted influence lines for individual axle loads are then superimposed graphically to obtain the effect of the entire vehicle. Beam and truss examples are given to illustrate the technique. A simple method is also presented for constructing influence profiles for compound systems, where the load is transferred through the deck and floor beams to the superstructure. Because of its graphical concept, the technique provides a practical approach for evaluating the force effects caused by an actual vehicular load; it is also well suited for teaching purposes.

Design Method II for vessel collision design is recommended by AASHTO specifications for most bridges. With its required resources more elaborate than Method I, Method II classifies vessel traffic passing under a specific bridge into different categories. To achieve an economical vessel collision design, a strategy is proposed to perform design Method II analysis on a statewide basis. In association with the waterways of Florida, the vessel traffic data are collected from available resources and a synthesizing methodology is developed to statistically process these data by vessel types, sizes, and loading condition. This study provides statewide input data ready for vessel collision analysis adopting Method II. As a numerical example, an illustrative bridge with multiple piers is designed in accordance with Method II. Waterborne traffic data from Indian River in Florida are utilized as input data. Comparison among annual frequencies of collapse due to various vessel categories indicates that barge trains are statistically significant in the collision design. Future traffic growth is considered using two different approaches and the possible difference is studied.

Experimental and analytical investigations were conducted to evaluate the effectiveness of isolating the superstructure from the substructure of a highly skewed prestressed concrete slab on a girder bridge. Dynamic testing of the bridge was performed using the pullback, quick-release method. A 3D finite elemental model of the bridge was calibrated and refined to match experimentally determined natural frequencies and mode shapes. Time-history analyses, using site-specific acceleration records, were conducted for the seismically isolated bridge model and an identical nonisolated bridge model. Seismic isolation was found to appreciably reduce forces that the bridge substructure and foundation must resist. When compared to the nonisolated bridge for the design earthquake (or 50-year event), the maximum pier moments were reduced between 32% and 62%, and the maximum shears were reduced between 30% and 66%.