Shrinkage tests of two full-scale composite trusses

1992 ◽  
Vol 19 (2) ◽  
pp. 296-309 ◽  
Author(s):  
D. J. Laurie Kennedy ◽  
Anita Brattland
Keyword(s):  
Concrete Beams ◽  
Concrete Slab ◽  
Shrinkage Strain ◽  
Steel Beam ◽  
Restrained Shrinkage ◽  
Test Results ◽  
Linear Strain ◽  
Shrinkage Behaviour ◽  
Composite Section ◽  
Composite Steel

The shrinkage behaviour of two composite trusses with a span of 11.5 m was studied. Shrinkage measurements to determine the effects of slab shrinkage on truss deflections and member strains were recorded over periods of 65 and 85 days. A method is developed to compute shrinkage deflections, based on equilibrium of the shrinkage-induced forces at midspan, which gives excellent agreement with the test results. This method assumes a linear strain distribution through the depth and is based on the free shrinkage strain of the concrete and the average stress–strain characteristics of the concrete in tension under restrained shrinkage conditions as it drys, creeps, and eventually may crack as it is gradually loaded from the green state. The method is extended to composite steel-beam concrete-slab members. It is equivalent to Branson's "composite section method" provided that the correct values for the shrinkage strain and the effective modulus of elasticity of the concrete in tension are used in the latter. Key words: behaviour, composite steel–concrete beams, trusses, shrinkage deflections.

scholarly journals Fragility Assessment of Beam-Slab Connections for Informing Earthquake-Induced Repairs in Composite-Steel Moment Resisting Frames

2021 ◽  
Vol 7 ◽  
Author(s):  
Hammad El Jisr ◽  
Dimitrios G. Lignos
Keyword(s):  
Concrete Slab ◽  
Epistemic Uncertainty ◽  
Steel Beams ◽  
Steel Beam ◽  
Fragility Functions ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Moment Resisting ◽  
Damage States ◽  
Composite Steel

Earthquake loss estimation in composite-steel moment resisting frames (MRFs) necessitates a proper estimation of the level of damage in steel beam-to-slab connections. These usually feature welded headed shear studs to ensure the composite action between the concrete slab and the steel beam. In partially composite steel beams, earthquake-induced damage in the shear studs and the surrounding concrete occurs due to shear stud slip demands. Within such a context, this paper proposes shear slip-based fragility functions to estimate the probability of being or exceeding four damage states in steel beam-slab connections. These damage states include cracking and crushing of the concrete slab in the vicinity of the shear studs, as well as damage in the shear studs themselves. The developed fragility functions are obtained from a gathered dataset of 42 cyclic push-out tests. They incorporate uncertainty associated with specimen-to-specimen variability, along with epistemic uncertainty arising from the finite number of available experimental results. An application of the proposed fragility functions is conducted on a six-story building with composite-steel MRFs. It is shown that steel beam-slab connections along the building height only exhibit light cracking (i.e., crack sizes of 0.3 mm or less) at design basis seismic events. At seismic intensities associated with a low probability of occurrence seismic event (i.e., return period of 2475 years) the nonlinear building simulations suggest that the 25% reduction of the shear stud resistance in steel beam-slab connections with beam depths of 500 mm or less is not imperative to maintain the integrity of the shear stud connectors.

Finite Element Analysis of Reinforced Concrete Beams with Exterior FRP Shell

2011 ◽  
Vol 243-249 ◽  
pp. 1461-1465
Author(s):  
Chuan Min Zhang ◽  
Chao He Chen ◽  
Ye Fan Chen
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Contact Interface ◽  
Accurate Calculation ◽  
Element Analysis

The paper makes an analysis of the reinforced concrete beams with exterior FRP Shell in Finite Element, and compares it with the test results. The results show that, by means of this model, mechanical properties of reinforced concrete beams with exterior FRP shell can be predicted better. However, the larger the load, the larger deviation between calculated values and test values. Hence, if more accurate calculation is required, issues of contact interface between the reinforced concrete beams and the FRP shell should be taken into consideration.

Concrete Beams Reinforced with GFRP Plates

2017 ◽  
Vol 747 ◽  
pp. 220-225
Author(s):  
Alberto Pedro Busnelli ◽  
Ruben Edgardo López ◽  
Jorge Carlos Adue
Keyword(s):  
Glass Fiber ◽  
Carbon Fibers ◽  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Glass Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
The World ◽  
Critical Resistance

This is the presentation of the research carried out by the Faculty of Engineering at Universidad Nacional de Rosario on the use of pultruded Glass Fiber Reinforced Polymer (GFRP) plates to increase the flexural strength of reinforced concrete beams.Pultruded plates are the type of elements made of composite materials which are most widely used for this kind of strengthening. Although around the world the material used for these plates is carbon fibers, its high cost prevents its widespread use in our country.One of the aims of our research program is, precisely, to verify whether it is possible to substitute such plates for significantly cheaper glass fiber elements manufactured in Argentina. The test results have proved that this alternative is feasible.What's more, the greater thickness of the glass fiber plates allows the use of additional anchor bolts. These bolts provide the system with post-critical resistance and ductility-characteristics which are absolutely necessary, for example, in structures in seismic areas.

Experimental Study on Specimens of Steel Secondary Beam Embedded in Reinforced Concrete Girder of Frame Structure

2011 ◽  
Vol 243-249 ◽  
pp. 1072-1084 ◽  
Author(s):  
Qiong Yu ◽  
Zhou Dao Lu ◽  
Jiang Tao Yu ◽  
Xing Zhuang Zhao ◽  
Jin Dai
Keyword(s):  
Reinforced Concrete ◽  
Cantilever Beam ◽  
Concrete Beam ◽  
Concrete Slab ◽  
Frame Structure ◽  
Secondary Beam ◽  
Steel Beam ◽  
Rotational Angle ◽  
Pullout Failure ◽  
Concrete Girder

Test of two specimens (four different joints) of steel secondary beam embedded in reinforced concrete girder in frame structure and one specimen with steel cantilever beam embedded in reinforced concrete girder under static load were conducted. The steel beam up-flange was pulled out because of the concrete cracks caused by the moment, shear and torsion at the upper zone of the concrete beam near the steel beam end. Shear failure of the concrete beam and the top flange pullout failure are the most hazardous failure modes. Lacking restraint of concrete and the reinforcement of steel bar in the concrete slab and catenary action of restraint steel beam, the capacity of steel cantilever beam is much smaller than other beams. Load-slip curve of top flange of steel beam, load-rotation curve of the steel beam end are obtained through experiment. Primary calculation method of joints flexural capacity related to section size of composite steel beam, embedded depth of steel beam, flange width of steel beam embedded end, height of frame girder, is put up with. Analytical results of ABAQUS are shown as follows. Top flange pullout failure of steel beam is caused by the detachment of concrete and steel beam end, and the warp of the concrete slab near the support plays an unfavorable action on the performance of the steel beam. The end rotational angle of the steel beam with anchor bar is smaller than that without. The steel beam with shear connectors develops a smaller rotational angle and a higher load capacity.

Influence of changing environment conditions on the development of shrinkage strain and the expansion coefficient of large concrete specimens

2019 ◽  
Author(s):  
Dominik Suza ◽  
Johann Kollegger ◽  
Harald S. Müller
Keyword(s):  
Shrinkage Strain ◽  
Theoretical Models ◽  
Test Results ◽  
Current Standard ◽  
Operating Life ◽  
Changing Environment ◽  
Temperature And Humidity ◽  
Bridge Structures ◽  
Standard Models ◽  
Creep And Shrinkage

<p>The standard creep and shrinkage strain measurements of concrete are usually conducted in a laboratory with constant temperature and humidity with a low variation. The creep and shrinkage measurements are conducted over a few months with the expectation that small concrete specimens can sufficiently describe the evolution of the rheology effects on a large multi-span bridge in the course of its operating life.</p><p>The monitoring of real bridge structures shows the actual progression of the deflections and concrete strains. Unfortunately the evaluation and interpretation of the measured values is complicated. The idea of the scientific Creep &amp; Shrinkage project was to combine the two described situations (laboratory experiments and monitoring of real bridge structures) creating an experimental setup which would benefit from the advantages of both approaches.</p><p>In order to achieve conformity of the measured test results with those of theoretical models (MC 2010, EC) it was necessary to upgrade the current models to include the effects of changing temperature and humidity. Within this paper the upgrade of the current standard models to include changing environment conditions will be elaborated, in addition to an explanation of the method used to separate shrinkage strains from the temperature strains from the measured data. The measured concrete expansion coefficients will also be discussed.</p>

High-cycle fatigue tests of pretensioned concrete beams

PCI Journal ◽  
2022 ◽  
Vol 67 (1) ◽  
Author(s):  
Jörn Remitz ◽  
Martin Empelmann
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Concrete Beams ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Design Methods ◽  
Test Results ◽  
Cycle Fatigue ◽  
Pretensioned Concrete ◽  
Current Design

Pretensioned concrete beams are widely used as bridge girders for simply supported bridges. Understanding the fatigue behavior of such beams is very important for design and construction to prevent fatigue failure. The fatigue behavior of pretensioned concrete beams is mainly influenced by the fatigue of the prestressing strands. The evaluation of previous test results from the literature indicated a reduced fatigue life in the long-life region compared with current design methods and specifications. Therefore, nine additional high-cycle fatigue tests were conducted on pretensioned concrete beams with strand stress ranges of about 100 MPa (14.5 ksi). The test results confirmed that current design methods and specifications overestimate the fatigue life of embedded strands in pretensioned concrete beams.

scholarly journals Influence of stirrup spacing on shear resistance and deformation of reinforced concrete beams

2018 ◽  
Vol 7 (1) ◽  
pp. 126
Author(s):  
Latha M S ◽  
Revanasiddappa M ◽  
Naveen Kumar B M
Keyword(s):  
Concrete Beam ◽  
Concrete Beams ◽  
Bending Moment ◽  
Maximum Load ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Cement Concrete ◽  
Simply Supported ◽  
Reinforced Cement ◽  
Flexural Reinforcement

An experimental investigation was carried out to study shear carrying capacity and ultimate flexural moment of reinforced cement concrete beam. Two series of simply supported beams were prepared by varying diameter and spacing of shear and flexural reinforcement. Beams of cross section 230 mm X 300 mm and length of 2000 mm. During testing, maximum load, first crack load, deflection of beams were recorded. Test results indicated that decreasing shear spacing and decreasing its diameter resulted in decrease in deflection of beam and increase in bending moment and shear force of beam.

Sign in / Sign up

Export Citation Format

Share Document