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Highlights • Possible failure modes are analyzed for modular GFRP-steel composite beams. • Theoretical formulation of bearing capacity is developed for each failure mode. • Flexural failure can be the critical mode for bidirectional composite beams. • Vertical shear failure can be the critical mode for unidirectional composite beam. • Ductile failure can be achieved with ultimate capacity larger than yield load. Abstract This paper analytically formulates the ultimate capacities for various failure modes of composite beams consisting of a modular fiber reinforced polymer (FRP) web-flange sandwich deck supported by a steel girder. Pultruded FRP box sections are incorporated between two flat panels to form the web-flange sandwich deck, in which the pultrusion direction of box sections can be either parallel or perpendicular to the span direction. Such a deck can then be assembled via adhesive bonding or blind bolt connections to a supporting steel girder to form a composite beam system. On the basis of theoretical analysis of critical sections for such composite beams at ultimate states, potential failure modes are identified, including flexural failure of the steel girder yielding in tension and GFRP deck failure in compression, vertical shear failure, and horizontal shear failure at adhesive bonding at bolted connections and at webs of FRP box sections. For each failure mode, the corresponding ultimate capacity is analytically formulated; thereby, the critical failure mode and ultimate load capacity can be determined. The developed ultimate limit design approaches are validated by experimental results from the literature for such FRP-steel composite beams. [ABSTRACT FROM AUTHOR]

The structural performance of bridge structures is temporal and is mainly controlled by the types of the applied loads. To continuously observe the structural performance of bridges, structural health monitoring sensors that include among many temperature sensors are used. The impact of nonuniform temperature distributions in bridge girders due to the environment thermal loads has been recognized by former researchers and bridge design codes. To evaluate these and other effects on the structural behavior of bridge structures, many field and experimental structural health monitoring studies were carried out. However, more researches are required to investigate the temperature distributions in other girder configurations. This work is directed to investigate the impact of air temperature and solar radiation on temperature gradient distributions in concrete-encased composite girders. For this purpose, an experimental concrete-encased steel girder segment was instrumented with thermocouples and other sensors. The experimental data recording continued for 6 months during the hot and cold seasons. Furthermore, a thermal finite element (FE) parametric study was conducted to investigate the effect of the girder size. The test results showed that the vertical and lateral temperature gradient distributions and the variation of the temperature gradients with time are controlled by the amount and location of the received solar radiations. The FE analysis showed that the daily temperature variations are higher in smaller girders, whereas the temperature gradients are smaller than in larger girders. Moreover, the FE results showed that the thickness of the girder's concrete members has an important impact on temperature gradients and temperature distributions. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive study on the application of global plastic design methods, not currently allowed in European specification provisions, to stainless steel rectangular and square hollow section continuous beams. The analysis of experimental and numerical continuous beam strengths highlighted that ultimate capacity predictions calculated based on global elastic analysis result in a considerable conservatism due to strain hardening and bending moment redistribution effects. Alternatively, the assessment and reliability analyses of the traditional plastic design methods demonstrated that the Class 1 cross-section limit provided in the European specification can be safely applied for the partial safety factor γ M0 currently provided. However, the analysis evidenced that including bending moment redistribution in capacity predictions is not enough since strain hardening effects play an important role when stocky cross-sections are analysed. Thus, the Continuous Strength Method for indeterminate structures was also assessed and it was found to provide accurate capacity predictions for all analysed stainless steel grades. Finally, an alternative Direct Strength Method design approach is proposed for stainless steel continuous beams based on the Direct Strength Method bending capacity. The proposed method, statistically validated, accounts for strain hardening effects and moment redistribution and provides the best resistance predictions among the different design methods considered. [ABSTRACT FROM AUTHOR]

A numerical investigation on cold-formed high strength steel (HSS) tubular beams is presented in this paper. The nominal 0.2% proof stresses of the HSS sections ranged from 700 MPa to 1100 MPa. In the complementary study [1], experimental investigation on the beam specimens have been performed. In the present study, numerical modelling methodology for beams was first validated and parametric study on the cold-formed HSS tubular beams was conducted. A total of 423 numerical data was obtained to investigate the structural performance of HSS tubular beams. The experimental and numerical results were then compared with the codified design guidelines from ANSI/AISC 360-10 [2], EN 1993-1-1 [3], AS 4100 [4] and AISI S100 [5] in addition to the predictions from Direct Strength Method (DSM) for square hollow sections (SHS), rectangular hollow sections (RHS) and circular hollow sections (CHS). The codified slenderness limits for sections subjected to bending were examined. Improvements on the design guidelines are proposed in this paper. [ABSTRACT FROM AUTHOR]

The reliability-based calibration of safety factors for the design of a simply supported steel beam, based on BS5950 (2000) is presented in this research work. The calibration was undertaken using a specialized computer program in Microsoft excel environment developed by the Joint Committee for Structural Safety (JCSS) CODE-CAL 2001. The design variables considered were modeled using the software, and the safety factors for the material, dead and live load were calibrated by varying the safety index. From the results obtained, mathematical prediction models were developed using a least square regression analysis for bending, shear and deflection modes of failure considered in the study. The results showed that the safety factors for material, dead and live load are not unique, but they are influenced by safety index and it was also shown that the safety factors for material, dead and live load vary from 0.61 to 1.15, 1.44 to 1.91 and 1.40 to 1.65 respectively for both bending and shear modes of failure. For deflection mode of failure, the results showed that the safety factors for material, dead and live load vary from 1.08 to 1.56, 1.10 to 1.17 and 0.83 to 1.25 respectively for target safety index (ßt) of 2.0 to 4.5. The mathematical prediction models developed for both bending and shear modes of failure are the same. Therefore, it is recommended that the mathematical prediction models developed in this study for bending and deflection modes of failure could be used when designing a simply supported steel beam to BS 5950 (2000). [ABSTRACT FROM AUTHOR]

Thin-walled cold-formed steel beams are investigated with existing experimental data and shell finite element simulations to characterize their in-plane moment-rotation behavior, up to and past peak strength, in local or distortional failure modes. Although ultimate strength prediction of cold-formed steel members is generally well addressed in design codes, pre- and post-peak member stiffness is only partially addressed; while member ductility and post-peak moment-rotation response suffers from a lack of any clear guidance. Without fundamental information on cold-formed steel moment-rotation/curvature response, i.e. the backbone curve, system modeling for cold-formed steel structures to collapse remains severely hampered. Existing data on cold-formed steel beams are used as the basis for the study conducted herein. Simplified moment-rotation models, motivated from ASCE 41 characterizations, defined with pre-peak flexural rigidity degradation, post-peak plateau and strength drop are explored by equating the area under the backbone moment-rotation response (energy) between the available data and simplified models. In-plane response of cold-formed steel beams is parametrized with new design expressions depending on local and distortional cross-section slenderness. This research provides work for potential incorporation into design standards such as ASCE 41 and AISI S100. Out-of-plane response of cold-formed steel beams, including lateral-torsional buckling, remains as needed future work. [ABSTRACT FROM AUTHOR]

In this paper we present a comparative analysis regarding the shear web resistance between five types of steel plate girders and a girder with corrugated webs. In the case of girders with corrugated webs, the design is conducted according to SR EN 1993-1-5:2008. The use of girders with corrugated webs is at its beginnings in Romania, due to the manufacturing technology that require automation, therefore the design is as well new to most of the engineers. Through the paper, we want to underline the improved behavior that girders with corrugated webs have upon their competitors, steel plate girders, and to give an example for the design of such girders. [ABSTRACT FROM AUTHOR]

Using steel fiber reinforced concrete (SFRC) causes significant improvement in the behavior of deep beams with openings. This paper proposed a method for designing SFRC deep beams with opening, which was derived from previous studies on the behavior modeling of SFRC beams under tension and design principles of strut and tie method. To evaluate the proposed method, four large-scale specimens were used, which included two SFRC and two reinforced concrete deep beams with opening. Results of the test series illustrated the applicability of the proposed method. [ABSTRACT FROM AUTHOR]

In designing a steel beam, one of the limit states is lateral torsional buckling. The value of the bending moment limit is called the critical moment. AISC specification only provides formulas for calculating the critical moment in prismatic beams, but not for non-prismatic beams like castellated beams. The objective of this paper is to study the lateral torsional buckling of castellated beams. The method used for this study is the collapse analysis using the finite element method, analyzed by ADINA 8.9. In the collapse analysis, a geometrically imperfect beam is loaded with an increasing load. At a certain value of the load, the lateral displacement increases progressively. The value of the maximum load is considered to be the critical load. In this study, the imperfection is taken 1/1500 of the unbraced length of the beam. The critical moment of castellated beam obtained from the finite element analysis is up to 42.31% lower than the critical moment of full beams with the same dimension calculated by using the AISC formula. Therefore, the correction factor for AISC formula to calculate the critical moment of the castellated beam is established. [ABSTRACT FROM AUTHOR]

Lateral wind loads often control the stability of bridge girders during construction stages in which the deck is not yet structurally effective. In this study, the key objectives were to experimentally quantify aerodynamic wind-load coefficients (drag, lift, and torque) for common bridge girder shapes and to quantify shielding effects arising from aerodynamic interference between adjacent girders. Wind tunnel tests were performed on reduced-scale models of built-up steel plate girders and prestressed concrete Florida I-beams (FIBs). Aerodynamic properties were measured for individual girder cross-sectional shapes and for systems of multiple adjacent girders (tested both with and without bridge deck formwork in place). Results from the wind tunnel tests, which revealed negative drag coefficients at selected downstream girder positions, were synthesized into simplified wind-loading cases suitable for use in bridge design. Wind-load cases were separately developed for assessing overall multigirder system stability and for determining the required strength of girder bracing between individual girders. [ABSTRACT FROM AUTHOR]

This study proposes a model of crack initiation and propagation in steel beams subjected to ultralow cycle fatigue. The model can be included in the general framework of lumped damage mechanics. A state variable called damage is introduced for each plastic hinge and can be related to the extension of the crack in the real structural component. The damage evolution law is based on the Manson-Coffin law, the Palmgren-Miner rule and two new concepts: the instantaneous plastic amplitude and a crack-driving variable. The model also describes crack closure effects using the unilateral damage assumption. It was validated by the numerical simulation of tests of steel beam-column connections subjected to cyclic loadings with constant and variable amplitudes, as reported in the literature. Advantages and limitations of the model are discussed for wider applications on the damage simulation of steel frame systems subjected to mechanical overloads, typically earthquake loading. [ABSTRACT FROM AUTHOR]

Recently, advanced transit systems are being constructed to reduce traffic congestions in metropolitan areas. For these projects, curved bridges with various curvatures are required. Many curved bridges in the past were constructed using aesthetically unpleasant straight beams with curved slabs or expensive curved steel box girders with curved slabs. Therefore, many recent studies have been performed to develop less expensive and very safe precast prestressed concrete (PSC) curved girder. One method of reducing the construction cost of a PSC curved girder is to use a reusable formwork that can easily be adjusted to change the curvature and length of a girder. A reusable and curvature/dimension adjustable formwork called Multi-tasking formwork is developed for constructing efficient precast PSC curved girders. With the Multi-tasking formwork, two 40 m precast PSC box girders with different curvatures were constructed to build a two-girder curved bridge for a static flexural test to evaluate its safety and serviceability performance. The static flexural test results showed that the initial cracking load was 1400 kN, exceeding the design cracking load of 450 kN. Also, the code allowed deflection of 50 mm occurred at a load of 1800 kN, verifying the safety and serviceability of the precast PSC curved bridge constructed using the multi-tasking formwork. [ABSTRACT FROM AUTHOR]

The diaphragm-through connections are some of the most widespread connections between concrete-filled steel tubular columns and steel beams. In this work, five tee-shaped diaphragm-through connections were fabricated so that they comply with the principle of ''strong members and weak panel zone.'' Low-frequency cyclic loading was applied to the specimens to investigate the panel zone behavior of the connections. Based on the test results, the force transfer mechanism and the effect of different factors on the panel zone shear capacity were analyzed. In addition, different methods of calculating the panel zone shear strength were compared with the experimental data. The results show that the shear capacity of the panel zone of the connection is borne mainly by the steel tube webs and the core concrete. The steel frame composite with steel tube flanges and diaphragms strengthens the plastic deformation ability after yielding. It was found that in the existing computational methods for panel zone shear capacity of the connection, the calculated results are in agreement with the test results for the shear capacity of the steel tube webs, but the predicted values are not consistent with the concrete component capacity. [ABSTRACT FROM AUTHOR]

In this paper, simplified mechanical models for the design of the top wind girder of large storage tanks adopted in the codes SH3046 and API650 were presented to show their differences regarding the wind load magnitude and action zone. Finite element models for the tanks were built to study the strengthening effects of the bottom constraints. It is found that for a large storage tank with a small ratio of height to diameter, the strengthening effects of the bottom constraints are significant and should not be ignored. If based on two-dimensional models without considering the strengthening effects of the bottom constraints, the strength design of the top wind girder according to the present codes of SH3046 or API650 is too conservative. [ABSTRACT FROM AUTHOR]

On one hand, stronger steel materials certainly yield more slender structural elements so that a beam design is structurally governed by its stability. On the other hand, there is a variation in the dimensions of steel sections and their availability in the market. Those issues will lead to a complex procedure in obtaining the optimum steel beam designs. Actually, computers will help to overcome the complexity of the problems. Meanwhile, the solution is generally limited to a specific steel section and a specific unbraced length configuration. As a result, some trial-and-error attempts are needed several times to obtain a sufficient comparison to determine the optimum steel sections. To overcome this, a strategy to use the AISC-LRFD's chart-based method, which plots the relationships between the flexural capacities of steel sections and their unbraced lengths of lateral bracing and weights, will be helpful in determining the lightest steel sections in terms of their lateral bracing requirements and capacity. In other words, the most optimum steel sections can be obtained without a specific trial-and-error process. However, the chart-based method for steel beam designs is not yet popular due to the absence of a choice of steel sections commonly found in the Indonesian market. This paper will present how to make the design curve of those steel sections; therefore, the chart-based method for steel designs can be implemented. Beside that, some examples of its usage will also be introduced. Thus, if the design with a chart-based method using the Indonesian steel sections can be provided; then, it can be used to design steel beams more quickly and economically. [ABSTRACT FROM AUTHOR]

This paper describes the design and construction of the steel composite Bridge G4 as part of the recently completed Egnatia Motorway project in northern Greece. The bridge crosses a 180 m wide, 70 m deep valley situated in a seismic zone. Following a value engineering study, a three-span bridge with incrementally launched deck was found to provide the best option with minimal disturbance to the environment. Due to the relatively high seismic design acceleration, the superstructure is considered to float on the substructure by means of high damping lead rubber bearings restrained by mechanical dampers at abutments. This paper describes the design and construction of Bridge G4. [ABSTRACT FROM AUTHOR]

Masonry flat arch diaphragm that developed in Britain is still in use in parts of Europe, North America, the Middle East, and Indian subcontinent. The damage of a large number of these diaphragms during past earthquakes all around the world highlighted the need for developing an appropriate retrofitting method. In this study, the in-plane seismic behavior of ordinary and the retrofitted brick flat arch diaphragms are experimentally investigated. Eight full-scale experiments were conducted under cyclic loading. Perpendicular and parallel loads were applied to the steel I-cross beams of the masonry flat arch diaphragms. The experimental models consisted of two frames of masonry flat arch diaphragms in the absence of brick flat arch, two ordinary masonry flat arch diaphragms with steel tension ties in end arch spans as prototype, two masonry flat arch diaphragms without and with steel tension ties in diaphragm span, and two retrofitted masonry flat arch diaphragms with simultaneous use of steel diagonal bracing and steel tension ties in end arch spans. The results of the experiments demonstrate that the ordinary masonry flat arch diaphragms have insufficient shear capacity and integrity. However, among the retrofitted models, the simultaneous use of diagonal bracing and steel tension ties in end arch spans improved the overall seismic performance, integrity, and ductility of the masonry flat arch diaphragm. Moreover, the stiffness and shear capacity of this diaphragm increased up to 108 and 88%, respectively. The findings of this study recommend the use of simultaneous diagonal bracing and steel tension ties in end arch spans for retrofitting the ordinary masonry flat arch diaphragms. [ABSTRACT FROM AUTHOR]

This paper develops a double nonlinear finite element model that can take account of both geometric and material imperfections. On verified the numerical model the behavior and ultimate carrying capacity of eccentrically loaded welded thin-webbed rectangular section columns made from high strength steel with a nominal yield stress of 460 MPa are analyzed, and further the influences of the slenderness ratio, web depth-to-thickness ratio, flange width-to-thickness ratio, and relative eccentricity ratio on the ultimate carrying capacity are investigated. On the basis of these, the simple calculation formulas, which use the gross cross-section properties, for predicting the in-plane maximum strength of high strength steel beam–columns with large depth-to-thickness ratios are proposed. It shows that the developed finite element model can simulate the local–overall interaction buckling behavior of the eccentrically loaded welded box-section compression members. A brittle failure characteristic is found with a relatively steeper drop just after the peak in the load–displacement curve. A nonlinear and complex stress distribution, in the longitudinal direction, when reaching the ultimate capacity, seriously deviates from an elastic stress distribution, on the basis of which, the effective width is determined. The non-dimensional ultimate bearing capacity is approximately linear with the slenderness, depth-to-thickness ratio and width-to-thickness ratio, respectively. The interaction curves between the axial force and flexural moment for the high-strength steel thin-webbed rectangular section beam–columns are nearly linear. After introducing a steel yield strength modification factor, the formula based on the edge fiber yielding criterion can precisely predict the local–overall interactive buckling strength of high strength steel beam–columns. [ABSTRACT FROM AUTHOR]

Through a programme of experiments, numerical modelling and parametric studies, the implications of allowing for strain-hardening in the design of laterally restrained continuous steel beams are investigated with particular emphasis on the performance of the bracing elements. A total of six tests were performed on continuous beams considering two basic scenarios: discrete rigid restraints and discrete elastic restraints of varying stiffness. In the latter case, the forces developed in the restraints were measured and compared to the design forces specified in EN 1993-1-1 (2005) for members containing rotated plastic hinges. Two different restraint spacings were considered in the tests to give non-dimensional lateral torsional slenderness values of 0.3 and 0.4 for the unrestrained lengths. In all tests, bending resistances predicted by the deformation-based continuous strength method (CSM) were exceeded. Using a standardised numerical model validated against the laboratory test data, a series of parametric studies were conducted; it was concluded that elastic restraints for members containing rotated plastic hinges should be designed to sustain higher forces than required for traditional plastic design if the full CSM collapse load is to be achieved. [ABSTRACT FROM AUTHOR]

Nowadays, girders with corrugated webs are used in bridges as an efficient alternative to conventional girders with flat stiffened webs. Particularly in bridge girders with corrugated webs (BGCWs), the corrugated webs are the main elements for bearing the shear forces. Instead of prismatic BGCWs, tapered BGCWs are currently used mainly due to their structural efficiency, providing at the same time aesthetical appearance. Available literature shows that tapered BGCWs may be classified into four typologies. Among these typologies, Case I is the most common case appearing commonly near to the intermediate supports of continuous bridges. Accordingly, in this paper, the finite element (FE) method is employed to investigate the inelastic behavior of tapered BGCWs of Case I, following to the fundamental behavior of such girders published recently by the current authors. Previously validated 3-D nonlinear FE models are developed and used in this study. The paper seeks, first, at finding the validity limit of the previously proposed design strengths for the tapered BGCWs with respect to the girder’s initial imperfection. This is made by considering different initial imperfection amplitudes. Accordingly, it is found that the proposed equation is valid with initial imperfections of h w 1 / 200 ; h w 1 is the height of the long vertical edge of the web panel. However, the accuracy increases for initial imperfections similar to the web thickness ( t w ) for cases of t w ≥ h w 1 / 200 . Then, it investigates the effect of the aspect ratio of the web panels, different flange inclination angles and flange slenderness ratios. Finally, the paper checks the authors’ previously proposed design model using the results of the generated parametric studies. Overall, the outcomes of this study are expected to provide more insight into the behavior of tapered BGCWs and enable accurate prediction of the shear capacity of this special type of BGCWs. [ABSTRACT FROM AUTHOR]

Most of the mass of steel plate girder bridge superstructures is concentrated in the reinforced concrete deck. During a seismic event, the inertia force that is generated in the reinforced concrete deck is transferred to the support cross frames through the headed stud connectors. Seismic analyses showed that these connectors are subjected to combined axial tension and shear forces. If not designed properly, these connectors may fail prematurely during an earthquake, altering the load path and subjecting other bridge components to forces they are not designed for. To verify these observations, two half-scale models of plate girder bridge subassembly were constructed and subjected to cyclic testing. The two specimens represented two different configurations of headed stud connectors in transferring the deck seismic forces. The connectors in the first specimen connected the girder top flange to the reinforced concrete deck, while the connectors in the second specimen connected the cross-frame top chord to the deck. These experiments showed that the connectors were indeed vulnerable under transverse lateral loading. The failure mode of these connectors is a combination between shear and tensile forces or concrete breakout. Based on this investigation, design equations were proposed and adopted in the AASHTO LRFD Bridge Design Specifications to evaluate the resistance of such connectors under shear and tensile forces. [ABSTRACT FROM AUTHOR]

This paper describes a method of the remaining life prediction of an aged RC-T girder bridge based on the concrete core test results. The remaining life prediction of the bridge can also be quantitatively estimated by applying the J-BMS with the field inspection data. It needs to be verified through the concrete core specimen tests extracted from some parts on main girders, deck slabs, and bridge piers, such as compressive strength, carbonation depth, chloride ion concentration, and so on. This study is focused on the performance and validation of the deterioration assessment used on concrete cores, which was collected from the target bridge. In this study, data obtained from collected concrete core specimens were examined by chloride ion and carbonation tests. As a result, carbonation is more dominant than the chloride ion on the deterioration process although the bridge is located within 1 km upstream from the mouth of the river pouring into the Seto Inland Sea. The carbonation rate coefficient and the apparent diffusion coefficient of chloride ions were determined, and the remaining life prediction where the main factor of deterioration is carbonation has been found from the concrete core test results. On the estimated cumulative amount steel corrosion (Q) of 75 mg/cm 2 , the remaining life of the bridge is predicted to be approximately 7 years. Also, the localized concrete core test results can be used for an entire span evaluation by visualized distribution results using an approximating function. [ABSTRACT FROM AUTHOR]

This paper presents an alternative technique for selecting the lightest W-section for beam-column members. Following the AISC procedure, the number of required steps to find a feasible section highly depends on the initial trial section. A new graphical technique based on the AISC interaction formula for designing steel beam-columns is proposed. By employing the newly developed diagrams, the new approach quickly leads to the lightest feasible section for a member subjected to combined biaxial bending and axial force. The number of computational steps in the proposed method is slightly reduced from the current AISC procedure. Some advantages of the new proposed method are converging to the solution in fewer steps, imposing no limit on Lb, considering the effect of Cb, considering biaxial bending by simply using a modification factor and covering cases where Lb is not equal to KL. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents a detailed finite element (FE) model intended for studying the distortional–global interaction buckling behaviour of thin-walled stainless steel beams. The model incorporated actual measured material properties of three stainless steel alloys (austenitic S30401, ferritic S44330 and lean duplex S32101), as well as measured initial geometric imperfections. The model was verified against the experimental data presented in the companion paper [1]. A parametric study was then carried out using the calibrated model to augment the ultimate strength database The accuracy of the Australian/New Zealand (AS/NZS 4673 [2]), American (SEI/ASCE-8 [3]) and European (Eurocode3, Part1-4 [4]) standards for stainless steel structures was evaluated using the available data. It was found that the current Australian/New Zealand and American design codes do not contain rules for checking distortional buckling strength nor do they account for distortional–global interaction buckling effects. The European standard accounts for distortional buckling effects by reducing the effective area of flange stiffeners using an effective thickness method, and covers the effect of distortional–global interaction by using the effective cross-section for overall buckling strength checks. The European code was therefore more conservative than the other two standards. Following the principles of the Australian and American design codes for cold-formed steel structures, additional provisions for checking distortional buckling strength were suggested to improve the current Australian/New Zealand and American stainless steel design codes. Variants of the proposed provisions to account for distortional–global interaction were also examined which resulted in generally better predictions than those of the European code. However, the distortional–global interaction effect was found to vary with the section slenderness, and none of the design provisions performed consistently better than others. [Copyright &y& Elsevier]

This paper presents the field evaluation of a damaged noncomposite steel girder bridge that is part of the interstate highway system in Vermont. This bridge is typical of late 1960s construction and spans over a two-lane state highway near the town of Weathersfield, Vermont. The superstructure contains three-span continuous girders supported on abutments at the ends and on RC multicolumn interior bents. Strains were measured during live-load testing that was conducted to better understand the bridge behavior. The field results were compared with results from finite-element models created using common engineering assumptions. In addition, the load-distribution characteristics of girders that were damaged by an overheight truck traveling on the state highway under the bridge were evaluated. The results indicate that alternate load paths were developed within the bridge superstructure as a result of damage from the truck impact. For the loading magnitude applied during the load tests, evidence of composite action was observed and participation of curbs on the response of the bridge was noticed. Bridge skew and partial restraint generated at the supports also contributed to differences in the observed and calculated responses. These nondestructive load testing results were used to provide confidence on the load-carrying capacity of the bridge and to avoid costly bridge closures and detours. [ABSTRACT FROM AUTHOR]

Shear connections develop a moment under the rotational demand imposed to them by the supported beam. For single-angle, double-angle, and tab to tubular column shear connections, this moment can be obtained through the equations derived from appropriate plastic yield line mechanisms. The primary application for the moment equations in the design of a connection is that the obtained moment can be used to estimate the load demand on the bolts and/or welds of the connection. This paper illustrated the moment equation method through various examples. Compared with the current empirical approaches in connection design, the proposed equation method is versatile and insightful. [ABSTRACT FROM AUTHOR]

The article discusses the paper "'Prefabricated Bridge Construction across Europe and America" by Robert Hällmark, Harry White and Peter Collin. The paper provides two examples of bridges constructed with prefabricated elements in Switzerland. Topics covered include the construction of a viaduct and the use of a concrete deck on steel girders of the bridges.

Two sections from a decommissioned bridge were salvaged and tested to quantify flexure and punching shear capacities. The salvaged bridge sections each consisted of two built-up, steel-plate girders, compositely attached to precast concrete, deck panels. The deck panels were part of an accelerated bridge construction (ABC) project and were connected to one-another using female-to-female, flexurally discontinuous, transverse joints. Experimental results were compared with theoretical-based results produced from AASHTO LRFD specifications design procedures. Measured flexural capacities exceed the AASHTO computational design capacity by 30%. The precast panels and transverse joints were also tested for punching shear capacity and found to range from 144 to 87% in comparison to the AASHTO LRFD values, depending on the proximity to the transverse joint. Nonlinear, finite-element models validated the experimental results. The analytical models had excellent agreement with experimental deflection, reaction forces, regions of yielding, and the ultimate flexural capacity. [ABSTRACT FROM AUTHOR]

Horizontally curved, steel I-girder bridges can present unique challenges for engineers and contractors because the curved geometry can result in a complicated torsional response. The most complicated stages for predicting behavior of the girders usually occur during erection and construction when the loads and support conditions are the most unpredictable. Although laboratory experiments can provide valuable insight into the behavior, the high cost of the specimens often precludes meaningful experiments, whereas field monitoring of bridges during construction provides invaluable opportunities to understand the behavior and gather data for validating computational models. A horizontally curved, steel I-girder bridge was instrumented to monitor the bridge during erection and concrete deck placement. Stresses were monitored as girders were lifted into position, followed by measurements of vertical deflections, rotations, and stresses during the concrete deck placement. The stresses during the erection process were relatively low owing to the proper use of lifting and placing methods; however, high stresses can be induced after girders are placed when the cross frames are ratcheted into position. As expected, higher stresses, compared with the steel erection process, were recorded during the concrete deck placement. Nonetheless, the monitored bridge did not have stability problems because the bridge utilized a relatively stocky flange width-to-depth ratio. For bridges more susceptible to stability challenges, such as tightly curved bridges, highly skewed bridges, narrow bridges, bridges with odd span arrangement, or some combination of these attributes, it is recommended that the designer consider the implication of slender girders and explicitly design for the possibility of construction-related stability challenges. In addition, resulting from the limited availability of field measurements of horizontally curved girders throughout the construction process, the data represent a valuable resource researchers can use to validate computational models for conducting parametric investigations. This paper outlines the methods used during the field monitoring and summarizes the results from the field measurements. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Behavior of Prestressed Steel Beams," that was published in volume 136, number 9 of the September 2010 issue of "Journal of Structural Engineering."