Evaluation and Load Rating of a Steel Girder In-Span Hinge Connection

Continuous steel plate girder bridges often use intermediate expansion joints located at in-span hinges to divide the superstructure into individual units with shorter expansion lengths. One common type of in-span hinge is often termed a “shiplap joint.” This type of joint is located away from piers near the moment inflection point of the span, maximizing girder efficiency. It consists of a cantilevered portion of the superstructure supporting a suspended portion of the latter on bearings placed on dapped portions of the steel plate girders. Few references are available for the evaluation and load rating of shiplap in-span hinges used in steel girder bridges. In this study, the strength and stability of a typical shiplap hinge connection is evaluated using two methodologies: a 3D finite element model including a detailed mesh of the connection; and a proposed simplified methodology based on design equations. Load ratings of the connections based on these methodologies are compared. The proposed approach allows for a conservative assessment of the hinge without the need for a detailed finite element model.

Development of Narrow Loop Joint for Precast Concrete Slabs with Fiber-Reinforced Mortar: Experimental Investigation of Material Properties and Flexural Behavior of Joint

In the replacement of the reinforced concrete slab in existing steel girder bridges, a loop joint is commonly used to join precast concrete slabs on site. However, a relatively wide joint is needed, and considerable time and effort are consumed to construct the joint due to the addition of transverse reinforcements to the joint on site. These disadvantages affect the progress of on-site construction and should be addressed, especially when this method is applied to highway bridges, where early traffic opening is necessary in many cases. This study proposes a narrow loop joint that has fiber-reinforced mortar without transverse reinforcements. Several material tests were conducted to determine a suitable material for the joint. A series of flexural loading tests of slabs was conducted to investigate the flexural behavior of the proposed loop joint with the selected material (polyvinyl alcohol (PVA) fibers). The results showed that the flexural capacity and deformation performance of the proposed joint with PVA fibers are equivalent to those of the conventional loop joint.

Evaluating Reserve Strength of Girder Bridges Due to Bridge Rail Load Shedding

This research experimentally and numerically evaluated the reserve strength of girder bridges due to bridge rail load shedding. The investigation included: (1) performing non-destructive field testing on two steel girder bridges and one prestressed concrete girder bridge, (2) developing validated finite element numerical models, and (3) performing parametric numerical investigations using the validated numerical modeling approach. Measured data indicated that intact, integral, reinforced concrete rails participate in carrying live load. Research results culminated in recommendations to evaluate the reserve strength of girder bridges due to the participation of the rail, as well as recommendations for bridge inspectors for evaluating steel girder bridges subjected to vehicular collision.

Load effects of overweight and oversize vehicle traffic on pavements and bridges

<p>Currently vehicle traffic regulations regarding on axle and total weights in Korea are simple, outdated and different from the regulations in other countries, such as US or European countries. In this study, load effect of over-loaded and special permit vehicle traffic on bridges and pavements are analyzed. Types of typical bridges include concrete and steel girder bridges. Types of pavements include asphalt and cement concrete pavements. Various weigh-in-motion (WIM) truck data are collected and used for comparing overweight ratios. Based on WIM truck data, load effects of various oversize vehicles mixed with common traffic are analyzed for various bridge types. Oversize vehicles include vehicles used in construction field, crane vehicles and transport vehicles for the military purpose. The effect of axle types on pavement design is also analyzed. The results of this study will be the basis of new provisions and regulations regarding on axle and total weights limitations as well as special permit vehicle.</p>