Concrete Deck Research Articles

Evaluation of force and dynamic factor on reinforced concrete deck slab through the static and transient dynamic tests

Evaluation of force and dynamic factor on reinforced concrete deck slab through the static and transient dynamic tests

Innovative composite floors for sustainable schools

This article describes a project to investigate the dynamic behaviour of a prefabricated timber-concrete composite floor slab developed for the Department for Education's GenZero sustainable schools programme. The GenZero initiative involves a new building system made of a kit of parts that could be manufactured off site and then assembled on site to create diferent confgurations of secondary school. The slab is constructed of a precast concrete deck on glulam ribs, with two interlayers. The project investigated the effect of both the interlayers and different shear connectors on the performance of the slab.

Flexural Behavior of Ultra-High Performance Concrete (UHPC) Deck with Joints subjected to an Improved Steel Wire Mesh (SWM) Treatment

Prefabricated Ultra-high performance concrete (UHPC) decks are often connected using UHPC wet joints to create the overall deck structure. The UHPC deck is, nevertheless, made weak by the fiber discontinuity at the contact interface. In this study, the fiber at the interface was made to serve as a bridge using an embedded steel wire mesh, and experiments were utilized to determine how the contact between the fiber and the steel bar affects the flexural behavior. The results show that the fiber significantly affects the ductility and flexural strength without reinforcement. The combined action of the fiber and reinforcement of the reinforced specimen somewhat increases the flexural capacity and ductility. The flexural capacity of decks with joints was finally calculated using three different ways, and it was found that the method that simplifies the tension and compression zones into rectangles is the most appropriate.

Detection and quantitative evaluation of pumping distress on bridge deck pavement through field and laboratory experiments

Pumping distress refers to the phenomenon of dynamic water entering a pavement, soaking the cement concrete layer to form slurry, and being pumped out of the pavement void under the action of traffic loading. Pumping distress is frequently reported in high temperature and rainy regions, such as Sichuan province in China. Various factors contribute to pumping distress on bridge decks, but most of these factors have merely been subjected to qualitative assessment. The aim of the study is to conduct a comprehensive quantitative analysis through three years of field investigations and laboratory experiments. The field investigations include ground penetrating radar (GPR), pavement permeability tests, skid resistance tests, and drainage facilities surveys. The quantitative analysis of the field and laboratory inspections revealed that the formation reason, deterioration rate, and damage degree of pumping distress were different between the truck and emergency lanes. The occurrence of pumping distresses was significantly related to the uneven construction of the bridge deck leveling layer, compaction segregation, and poor drainage. Additionally, the influence of pavement thickness uniformity on pumping distress was evaluated by incorporating GPR techniques. Failure in the waterproof adhesion layer resulted in the barrier between the cement concrete deck and the asphalt mixture breaking, which allowed alkaline sources to move and transfer to the pavement layer easily. The outcomes of this study can help bridge authorities and construction contractors choose appropriate design and construction measures to prevent pumping distress.

Experimental and numerical investigations of the effects of various tensile reinforcement types on the structural behavior of concrete bridge deck slabs

Fiber-reinforced polymers (FRPs) have attracted attention owing to their ability to solve steel corrosion problems. However, FRP-reinforced concrete (RC) deck slabs were found to fail in a brittle shear manner due to the low stiffness of the FRP bars. In contrast, steel-RC deck slabs failed in ductile flexural failure by yielding of steel reinforcement. This study attempts to avoid such brittle failure in FRP-RC slabs by using hybrid steel/FRP bars that can provide serviceability, high strength, and durability. Seven full-scale reinforced concrete bridge deck slabs were cast and tested under four-point loading up to failure. The slabs were 3100mm length × 1000mm width × 200mm thickness. The investigated parameters were the reinforcement type and ratio and different patterns of the hybrid system. Subsequently, a finite element model was constructed, and the model results were compared to the experimental test results. Moreover, a numerical study was carried out by studying the different parameters affecting the shear behavior of RC members, such as the reinforcement ratio, FRP-to-steel ratio and wide range of the shear span-to-depth ratio. Based on the test results, Hybrid-RC slabs showed flexural-shear or compression-shear failure with ample warning than that reinforced with pure BFRP bars. Increasing the reinforcement ratio enhanced the overall slab performance at serviceability limit state. Furthermore, the numerical study indicated that the FRP-to-steel ratio should be Af/As ≤ 1.0 for achieving favorable ductile failure.

Experimental study and analysis for the long-term behavior of the steel–concrete composite girder bridge

Due to the influence of the meteorological factors, the long-term behaviors of steel–concrete composite girders of the real bridge is different from that of indoor laboratory models. In order to address this issue, a long-term field test of 4 years was performed on the simply-supported steel–concrete composite girder bridge to study the temperature, shrinkage and creep effects. The temperature field models (TFM) and mechanical behavior models (MBM) were built in sequence and verified by the test results of the concrete deck and steel girders of 2018 and 2019 since the temperature and strain changed greatly during this period. The temperature calculated by the TFM agreed well with the test results. Although the stress of composite girders obtained by the test is different from that of the MBM, the difference in the whole service stage is small. The test results of the steel cross beam, the steel–concrete interface, the wet joint and the concrete continuous layer were also discussed, and the former three were all under compressive state, while the concrete continuous layer is under tensile state in some time period with the maximum tensile stress 3.12 MPa. Then, the verified models were used to separate the temperature strain from the long-term tested strain, and the remaining tested strain is the shrinkage and creep strain. In summer and winter, the shrinkage and creep stress calculated by the age-adjusted effective modulus method (AEMM) was different from the tested values due to the influence of air humidity, initial load age, stress level and inherent error of the prediction model. Much attention should be paid to the influence of the meteorological factors on the long-term behaviors of steel–concrete composite girder bridges.

An Experimental Study on the Flexural Performance of a Steel-ECC Composite Bridge Deck Sheet in the Negative Moment Zone

This paper seeks to solve the problem of orthotropic anisotropic steel deck pavement being prone to damage and fatigue, and to study the negative moment performance of steel-ECC concrete composite deck slabs. In this work, four groups of eight specimens were designed for the negative moment four-point bending test study, which included four variables of two ECC slab thicknesses and two bolt spacings. By analyzing the damage mode, crack distribution characteristics, bending load capacity, load-deflection curve, and load-strain curve, the effects of different ECC slab thicknesses and bolt spacings on the bending performance, deformation capacity, and cracking behavior of the steel-ECC composite bridge deck were investigated. The test showed that the combined structure of the ECC and steel plate showed good integrity and good ductility under a negative bending moment, and the damage mode of the member was pure bending of a section of the ECC with concrete cracking damage. When the thickness of the ECC plate increased from 50 mm to 75 mm, the ultimate flexural load capacity of the specimen increased by 92.6%, and when the distance between bolts was reduced from 200 mm to 150 mm, the ultimate flexural load capacity of the specimen increased by 13.4%. The increase in the ECC layer thickness increases the ultimate bearing capacity of the specimen significantly, and the decrease in the bolt spacing increases the ultimate bearing capacity of the specimen less.

Optimal Design of Bubble Deck Concrete Slabs: Sensitivity Analysis and Numerical Homogenization

The use of layered or hollow floors in the construction of buildings obviously reduces the self-weight of the slab, and their design requires some expertise. In the present work, a sensitivity analysis and numerical homogenization were used to select the most important characteristics of bubble deck floors that have a direct or indirect impact on their load capacity. From the extensive case study, conclusions were drawn regarding the optimal selection of geometry, materials, and the arrangement and size of air voids in such a way as to ensure high stiffness of the cross-section and at the same time maximally reduce the self-weight of the slabs. The conducted analyses showed that the height of the slab and the geometry of the voids had the greatest impact on the load-bearing capacity. The concrete class and reinforcement used are of secondary importance in the context of changes in load-bearing capacity. Both the type of steel and the amount of reinforcement has a rather small or negligible influence on the bubble deck stab stiffness. Of course, the geometry of the voids and their arrangement and shape have the greatest influence on the drop in the self-weight of the floor slabs. Based on the presented results of the sensitivity analysis combined with numerical homogenization, a set of the most important design parameters was ordered and selected for use in the optimization procedure.

Noncomposite concrete deck bracing effects on continuous steel stringer lateral torsional buckling resistance

Louisiana’s bridges used two-girder or truss systems in the 1950 s and 1960 s, in which floorbeams are carried by main members and continuous stringers are supported by the floorbeams. The main members are either two edge (fascia) girders or trusses. Continuous span stringer bottom flanges are in compression in their negative moment regions, which could result in lateral torsional buckling (LTB). When these stringers are load rated using AASHTOWare Bridge RatingTM analysis software, lateral torsional buckling (LTB) resistance is calculated in accordance with the AASHTO LRFD Bridge Design Specifications, which the authors have determined may not adequately account for bracing effects provided by a noncomposite deck, and therefore could underestimate the flexural strength. Resulting ratings may be low enough to require restrictive, and possibly unnecessary, load postings or even bridge closures. This issue affects more than 20 significant bridges that are key parts of Louisiana’s highway system. To address the challenge of underestimated stringer LTB resistance and assess bracing effects provided by a concrete deck, experimental and analytical studies were performed on a two-span, continuous, steel stringers in a grillage system, which included three stringer lines, an interior transverse support (floorbeam), and transverse diaphragms at the end supports. The tests encompassed a variety of configurations, with and without a concrete deck. This paper describes laboratory testing setups and discusses experimental results, focusing on bracing effects on LTB resistance due to the presence of a noncomposite concrete deck. Finite element models using ANSYS were calibrated, validated using test results and used to simulate stringer behavior in Louisiana’s representative bridges. Finite element analyses of various tests showed generally comparable results to test data, and provided a feasible approach to load rate continuous stringers if a refined analysis is deemed necessary. The studies showed that stringer LTB resistance could possibly be tripled when noncomposite deck bracing effects are considered.

Time-dependent reliability-based charts to evaluate the structural safety of RC wharf decks exposed to corrosion and freeze-thaw effect

User-friendly time-dependent reliability-based evaluation charts are developed in this research to help practitioners assess the structural safety of existing steel reinforced concrete wharf decks exposed to chloride-induced corrosion and freeze–thaw effect. The research methodology consists of developing a time-dependent reliability-based algorithm using Monte Carlo (MC) simulation, conducting a sensitivity analysis to identify influential parameters that affect the wharf reliability, and calibrating user-friendly evaluation charts. Design examples were provided to demonstrate the use of the evaluation charts for predicting the structural safety of wharves subjected to gravity loads. The margin of error of using the developed charts was found to be less than 2.5% as compared to rigorous time-dependent crude MC simulation.

Investigation of the Pier Response during the Lateral Slide of Multi-Span Bridges

Lateral slide-in bridge construction—also referred to as slide-in bridge construction (SIBC)—has gained increasing attention as a viable accelerated bridge construction (ABC) approach. Although SIBC has been successfully employed on multiple single-span bridge projects, the use of SIBC on multi-span bridges is rare. Adding more spans creates a more complex system that requires connections (and other details) that were previously not needed in a single-span slide. Also, it is a concern that the multi-span bridge would need to slide on piers, which creates possible uplift and overturning scenarios. As such, it was vitally important to understand the structural response of the substructure during the bridge sliding. Although much general information on lateral slides as an ABC method was available, very little literature had been published related explicitly to such construction for multi-span bridges. The objective of this research was to develop durable design details to be used with the lateral slide concept with a focus on pier connection details and evaluate the performance of the bridge pier during the sliding. To achieve the goal, relevant information was collected and evaluated by conducting a literature review on various details and construction approaches for previously completed lateral slide projects. Further, a three-span, 300 ft long steel girder bridge on IA 1 southwest of Iowa City, Iowa, U.S., was monitored using gauges during the slide-in. The results indicated that the current slide-in practice works well with the multi-span steel girder superstructure and the wall pier. No significant response from the substructure was visually observed during the slide-in, and no cracking occurred on the concrete deck or piers. This indicated that the superstructure with steel girders and concrete diaphragms could be built with the lateral slide-in method. The significant strain was measured from the pile strain gauges. However, the piles were functionally adequate to carry the vertical load, and the moment carried by each pile was minimal. An uplifting action was captured on Pier 1. However, this effect was minimal on Pier 2.

Assessment of the low-temperature performance of asphalt mixtures for bridge pavement

The alternative Stone Mastic Asphalt containing an increased amount of bituminous mastic bituminous mixtures (SMA-MA) have been successfully used for additional protective layers on steel and concrete deck bridges. In this application, the mixtures must feature the desired behaviour at both high and low (i.e. below freezing) temperatures. The SMA-MA mixtures owe their improved low-temperature resistance to the bituminous binder used in them, softer than the binders used in mastic asphalts (MA). This article reports a study comparing the selected low-temperature parameters of the SMA-MA and MA mixtures to the parameters of the bituminous binders used in them. The performance of HMA was evaluated by subjecting the specimens to UTST (Uniaxial Tension Stress Test) and TSRST (Thermal Stress Restrained Specimen Test) tests at the test temperatures from −25°C to −10°C. The low-temperature performance of bituminous binders was, in turn, assessed with the BBR test.

An Analytical Model to Evaluate Short- and Long-Term Performances of Post-Tensioned Concrete Box-Girder Bridges Rehabilitated by an Ultrahigh-Performance Concrete Overlay

Potentially unfavorable stress redistributions could occur in post-tensioned concrete box-girder bridges upon deck rehabilitation by an ultrahigh-performance concrete (UHPC) overlay. The reason for such redistributions is that the deck forms an integral part of the load-resisting mechanism so that deck rehabilitation, namely, the process of removing the deteriorated deck and casting a fresh UHPC overlay, may cause large stress redistributions in the box girder. In addition, the significantly different shrinkage behavior between the freshly cast UHPC deck overlay and the old existing concrete deck below would result in restrained stress in the UHPC–old concrete interface. Therefore, how to evaluate the stress redistributions and the potentially unfavorable stresses in the box girder resulting from construction operations and the incompatible shrinkage is a crucial issue. Here, we propose an analytical model to assess the short- and long-term performances of the concrete box girder during and after deck rehabilitation. The analytical model was verified by using finite-element models incorporating the staged construction simulation and time-dependent behavior of materials. The model can be easily established and calculated with a great amount of time-saving compared with finite-element modeling, and it applies to different types of post-tensioned concrete box-girder bridges. The analytical model involves the balancing-load concept and the age-adjusted effective modulus method (AEMM). The balancing-load concept in the short-term analysis is to account for the prestressing force, and the AEMM in the time-dependent analysis is an effective tool to determine how stresses and strains vary with time due to the creep and shrinkage of a UHPC deck overlay. A parametric study was then conducted based on the analytical model, which involved the thickness of the deck layer to be rehabilitated and the addition of steel reinforcement in the new UHPC deck overlay. Analysis results indicated that pronounced tensile stresses developed in the UHPC deck overlay, which resulted from the restraint of the free shrinkage of the UHPC overlay by the subjacent concrete deck. An increase in the thickness of the newly cast UHPC deck overlay resulted in a decrease of the tensile stress in the UHPC deck overlay, and a rehabilitation thickness of 3.8–5.1 cm (1.5–2.0 in.) was deemed appropriate for the selected bridge according to the analysis.

Hygro-thermal–mechanical coupling analysis for early shrinkage of cast in situ concrete slabs of composite beams: Theory and experiment

The steel girder of the steel–concrete composite bridge restricts the deformation induced by variations in the temperature and relative humidity of the concrete. Thus, concrete component is prone to early cracking, which significantly impacts its durability. This study investigated the hygro-thermal–mechanical behaviors and early cracking mechanism of the concrete slab in composite beams using field measurements of composite beams and coupled finite element simulation. The findings demonstrate that temperature significantly impacts relative humidity development and that temperature and relative humidity are the primary determinants of early stress development of concrete. Then, a parameter study was conducted with four working conditions, including adiabatic boundary, heat open boundary, moisture-heat open boundary for the upper surface, respectively, as well as the test condition, to investigate the impact of temperature and humidity convection on the cracking of the concrete during the curing period. The results indicate that, whereas ambient humidity mainly influences the incidence of shallow cracks, ambient temperature significantly impacts early cracking that can fully propagate inside the concrete deck with thickness less than 25 cm. The existence of steel girder alters the original temperature boundary of the concrete surface at the steel–concrete bonding interface, which then directly or indirectly influences temperature and relative humidity distribution and stress of the concrete slab in the nearby 5–10 cm range and even causes the concrete enormous cracking risk. For the composite beams cast in volatile environments, consideration should be given to the excellent thermal conductivity of the steel girders. Heat preservation and moisture retention needs of the cast-in-place steel–concrete composite beam should be appropriately enhanced to prevent early cracking of the concrete deck.

Comparative Assessment of Variable Loads and Seismic Actions on Bridges: A Case Study in Italy Using a Multimodal Approach

The structural safety of the infrastructure stock is an important issue in modern seismic performance assessments. Following recent seismic events, reports have highlighted the increased vulnerability of physical infrastructural assets, particularly for many bridges across the Italian road and motorway network. Italy possesses one of the most complex and intricate road systems in Europe which was constructed across irregular territories in terms of plan and elevation and of varying dimensions. As such, a comparative case study is presented herein. This case study aims to characterise the seismic vulnerability of the Vizzana-Zampogna viaduct which is part of the A15 Parma-La Spezia motorway, near the locality of Selva Bocchetto. The viaduct is considered representative of the 1970s construction period. It is approximately 342 m in length and is characterized by a flat curvilinear prestressed concrete deck consisting of 15 spans simply supported on reinforced concrete piers. To better understand the seismic structural response of the individual piers of the viaduct, a “multi-modal” nonlinear static analysis was developed, which allows the effects of sectional stresses relative to the variable load profiles of the single modes to be combined through the quadratic modal combination, and to be compared with the relevant limit state. The research aims to qualitatively identify the piers most vulnerable to seismic action and to study the effects that are induced by introducing variable loads and intensity scenarios of different earthquakes.

Evaluating the Effect of Incorporating Slag Cement with Pre-wetted Lightweight Aggregate on Reducing Cracking of Concrete Bridge Decks

Abstract Early-age cracking is a severe problem in concrete bridges because it reduces the durability of the superstructure. One of the techniques to minimize early-age cracks is the addition of pre-wetted lightweight aggregate (LWA). There is limited research regarding the effect of pre-wetted LWA on the early-age performance of concrete. This paper aims to evaluate the efficiency of incorporating slag cement with pre-wetted LWA to reduce the potential cracking of the concrete decks. Also, the effect of fly ash on the shrinkage properties of concrete was investigated. Mixtures used in this study consist of replacements of total aggregate with pre-wetted LWA and partial replacements of cement with slag cement or fly ash. The performance of concrete specimens containing slag cement with pre-wetted LWA was evaluated in terms of mechanical properties, plastic shrinkage, free shrinkage, and restrained shrinkage. The results showed that the tensile strength was not the most significant parameter affecting the cracking potential of the concrete. The cracking potential of the concrete was strongly related to the tensile strength and free shrinkage. It was observed that incorporating slag cement with pre-wetted LWA significantly enhances the early-age performance of concrete as the tested specimens showed no sign of cracks. The results also showed that the shrinkage of the mixtures containing coarse LWA was reduced by 43 % compared with the control mixture. Moreover, it was noted that the LWA with higher absorption increases plastic shrinkage cracks for concrete decks under severe conditions.

COMPOSITE BRIDGES WITH CRACKED CONCRETE DECK SPANNING BETWEEN TRANSVERSE BEAMS UNDER FATIGUE SHEAR LOADING

AbstractFor concrete deck of large steel‐concrete composite road bridges cracking occurs due to tension because of negative bending moments at the support area, at the same time traffic load with high wheel loads passes the deck spanning between transverse beams. They induce cyclic shear loading in the cracked concrete deck. In composite bridges the application of prefabricated concrete elements has led to economical designs with a benefit in construction time. In this case, the prefabricated concrete elements are supported by the transverse beams when the on‐site concrete is poured. For this construction, the concrete is subjected to tension forces resulting from the global load‐carrying effect, which needs to be superimposed with local effects as wheel loads acting as shear fatigue loading. In this paper, the fatigue strength of cracked concrete deck under tension and shear fatigue loading is discussed.

Full-Scale Floor System Testing for Future Hot-Rolled Asymmetric Steel I-Beams

The presented study conveys the initial full-scale experimental study for future hot-rolled asymmetric steel I-beams, termed A-shapes. The primary use for these beams is residential building floor systems. Current systems commonly utilize concrete solutions, which achieve a shallow depth for optimal floor-to-floor heights. However, these floor systems are relatively slow to construct because of the amount of formwork, rebar and post-tensioning placement, and shoring needed. The shallow-depth steel-concrete floor system concept explored in this research aims to improve the speed and efficiency of residential building construction. This increase in speed is achieved through hot-rolled steel A-shapes, which reduce the fabrication time for beam production. These steel shapes have a wide bottom flange that can support precast concrete panels or deep metal decking. Therefore, a relatively easy to assemble shallow-depth system can be achieved. The research study presented herein includes the experimental feasibility testing of a full-scale shallow-depth steel-concrete floor system to further the knowledge of A-shape performance in such systems. The floor system concept evaluated consisted of three steel A-shapes, precast hollow-core concrete panels, and a cast-in-place concrete topping slab. The testing involved taking measurements during construction, service live loading, and loading of the system to failure. The major unknowns were constructability, stability during construction, live load performance, and composite behavior. This experiment revealed that the system was constructed easily and rapidly and also remained stable during construction. The system performed well under service live load, experiencing deflections equivalent to L/3,000. The system failed due to the bond breaking between the concrete and steel, going noncomposite after experiencing partially composite behavior. This occurred at an actuator load equivalent to five times the design service live load. All of this indicates that the floor system concept using A-shapes is a legitimate path forward to faster construction of residential facilities. This validates the need for the research toward standardized A-shapes in the United States.

USE OF HIGH‐ STRENGTH STEEL FOR SLENDER MEDIUM SPAN BRIDGES: TWO RECENT CASE STUDIES IN FRANCE

AbstractThis paper presents two cases of existing bridges with prestressed concrete deck replaced by composite steel‐concrete decks. The new decks provide a larger carriage width with increased load carrying capacity according to current design requirements. Furthermore, they have less piers (and therefore larger spans) but still keep the same construction height of the previous solutions. This leads to very slender continuous decks which are an optimal field of application for high‐strength steel. The technical solution adopted is an evolution of the traditional technology of composite steel‐concrete deck, commonly used in the span range between 20m and 40m.

Application of CFRP Tendons to Novel Connections of Precast Concrete Deck Panels: Experiments and Analytical Models

Application of CFRP Tendons to Novel Connections of Precast Concrete Deck Panels: Experiments and Analytical Models