Papers by Keyword: Load Test

Abstract: In prestressed elements with shear reinforcement, according to the current design procedures EN 1992-1-1 (2004), the effect of axial force is taken into account by using a lower angle θ of the compression concrete strut compared to reinforced concrete elements. However, there is no direct procedure for calculating this angle and it is up to the experience and discretion of the designer, who may take into account the recommendations of the authors of professional publications. The article deals with the theoretical evaluation and experimental load test of the shear resistance of prestressed beams. It examines the effect of axial force on the shear resistance with shear reinforcement, which in the analyzed element is greater than that defined by the minimum degree. The theoretical analysis evaluates the approach of the design model for shear with shear reinforcement according to EN 1992-1-1 with experimentally obtained values. The analysis is also based on the results of an experimental campaign. The beam with a standardized cross-section, which is still used today for concrete road bridge structures, was tested. The full-scale experiment was therefore carried out on a 600 mm high beam with an I-shaped cross-section. The total length of the experimental beam was 7.0 m, while the effective span of the beam during testing was 4.9 m, which allowed obtaining 2 results from testing one element. The result is the demonstration of a positive influence of axial force on the shear resistance of an element with shear reinforcement, although the level of influence is not significant.

Abstract: The subject of the article is a description of the behaviour of a developed fully composite footbridge structure, with a focus on its subsidiary load-bearing elements. The bridge is built using a modular system, and is designed for temporary use. The load-bearing structure is composed of wall beams acting in the longitudinal plane of the footbridge, along with transversely oriented beam elements that form a basic structural module in the shape of the letter "U". The module's structure is supplemented with stiffening frames at the ends, which prevent horizontal deformations of the wall elements and contribute to the connection of additional modules. The connection of the individual modules is carried out by means of steel tabs in the tensioned and compressed parts of the wall beam and by bolting through the adjacent stiffening frames, thus transferring the shearing force. The walking bridge deck is made up of composite grates with an anti-slip coating, which are placed on pultruded profiles acting in the transverse direction. A numerical model was developed to predict the behaviour of the footbridge, the accuracy of which was verified by comparing the results from a load test that was carried out. The test specimen consisted of four modules, and the total length of the footbridge was approximately 8.0 m. For loading purposes, water tanks (tank capacity 1000 l) were distributed over the entire footbridge area to simulate a uniform area payload. Loading was carried out at three defined levels of design surface load. In addition to the uniform full-area loading, asymmetrically applied loading conditions were also performed.

Abstract: This paper presents the results of testing and the first application of a newly developed innovative system of the bridge superstructures made of UHPC material. Being designed for footbridges it is called short span footbridge system - SSFS. This system was developed for a wide range of uses mainly as footbridges for pedestrians and cyclists and without waterproofing or surfacing. Prestressed prefabricated elements work as single-span beams with a span of up to 20 meters. Thanks to the optimization of the geometry design and the advantageous use of the mechanical properties of the UHPC material in combination with the prestressing, it was possible to achieve a very small construction height. These subtle and light load-bearing components tend to move away from traditional concrete structures, their span-to-depth ratios are closer to steel beams, but the needs for corrosion protection are eliminated using UHPC, which is inherently very durable and therefore almost maintenance-free. SSFS elements can be manufactured with a variable width of up to approx. 3.2 m, but they can be connected transversely and therefore the width of the structure is not limited. The first part of the paper is devoted to the development of the system and real applications of the first few footbridges made of UHPC material and other possibilities of this technology for future applications. The second part of the paper mentions the design and experimental verification of anchoring devices that are used to manipulate small-span footbridges made of UHPC.

Abstract: This article presents the results of the experimental development of a unique bridge system consisting of timber beams connected with bridge deck segments made of Ultra-High Performance Concrete (UHPC). The article deals with the production of a full-scale prototype of the timber-concrete composite structure and with an execution of a subsequent load test. The test structure was 3.30 m wide and 10.24 m long and was designed as two beams made of glue laminated timber connected with subtle bridge deck segments with a thickness only 60 mm and with a typical length of 1.50 m. The aim of the production of the test structure was to check some production details and procedures and subsequently to verify the behavior of the composite structure under load by the load test. The load test was performed with a theoretical span of 9.50 m as a four-point bending test to failure. After the overall load test was done, some bridge deck segments were cut from the structure and a load test of the bridge deck in transversal direction were executed to verify the behavior and the load-bearing capacity of the bridge deck segments made of UHPC.

Abstract: This paper presents the results of two load tests carried out in a continuous flight auger pile of 0.4 m in diameter and 12 m in length. The pile was instrumented in depth with strain gages in order to obtain the load capacity along the shaft and the tip. The load tests were carried out at the University of Campinas Experimental Site Test. The subsoil where the pile was installed is constituted by a first stratum of Silty Clay, which is porous and collapsible, of 6.5 m in thickness, followed by a stratum of residual soil of Clayey Silt up to 14 m depth. The first load test was the slow type, and a quick load test in the same pile after five days. From the results obtained with the use of instrumentation, the values for both lateral and tip load were determined in each one of test carried out in the pile studied. With these results and applying the Cambefort’s Law, it was could evaluate the evolution of the shaft friction and tip load in relation to the associated settlements, as well as the occurrence of residual load. The ultimate load obtained in the test was 960 kN and 810 kN for the first and second tests, respectively. The stress for the tip was 853 kPa and 655 kPa for the first and second tests, respectively.

Abstract: This paper deals with the modeling of the load test of vertical resistance of reinforced concrete piles. The pile is a part of a group of piles with reinforced concrete heads. The head is pressed with steel arches of a bridge on highway Jablonov - Studenec. Pile model is created in ANSYS with several models of foundation having properties found out from geotechnical survey. Finally some crucial results obtained from computer models are presented and compared with these obtained from experiment.

Abstract: The paper deals with design of model and verification of a pile loaded by pressure. The pile is embedded in the layered ground mass. Its model has been created using the ANSYS software system. The obtained results have been compared with results of the pile loading test performed during the construction of a multifunctional building. In the conclusion the results have been presented in graphs.

Abstract: It is well known that a lot of concrete filled steel tubular (CFST) arch bridges were built in China. Thus it became a main bridge type. Its architectural design shows much novelty, while the structural design is always conducted based on the finite element (FE) model analysis. Meanwhile there is no professional code for design and construction of this type of bridge. To overcome these disadvantages, scaled model tests are preferable to evaluate the mechanical behavior and provide guidelines for design and construction of prototype bridges. In this paper, an irregular CFST arch bridge as the prototype was introduced and a 1/16 scaled bridge model was designed and constructed according to the similarity theory. The experimental study on the scaled model was aimed to simulate the construction stages and mechanical behavior under moving loads. The test results are used to make comparison with the construction monitoring and bearing-capacity load test of the prototype. The analysis shows that the experimental results of the scaled model are close to the measured results of the prototype. The scaled model test was proved to be valuable for the pre-camber setup of the arch rib and the tension optimization of the suspenders and for the operation safety.

Abstract: The article deals with diagnostics of a historical bridge using measuring methods and inverse analysis and presents selected results of the pilot project implemented for the Railway Infrastructure Administration, state organization. The main task is to fulfill the function of an owner/operator of the national and regional railway owned by the state in Czech Republic. Main results of the project will be used for the reconstruction of the similar historical bridges on railway lines in the Czech Republic. Non-geodetic measurements include the determination of actual module of elasticity of the masonry, which was determined by direct measurement of the selected bridge support. Geodetic measuremets include long-term (seasonal epochs) and short-term (continuous during the load test) monitoring of geometrical deformations of the “Křenová” historical railway bridge construction in Brno.

Abstract: Today there are a lot of sophisticated methods to measure and analyse a bridge during load tests as a GPS, photogrammetric measurements, laser scanning, etc., The use of an classical techniques as trigonometric hights is still good enough for most demanding field observations. In practice control measurements are performed with the help of geodetic measurements, of which the basic goal is to capture any geometric changes in the measured object, or its displacements and deformations are found. In this article the use of trigonometric hights during a load test on the biggest Slovenian viaduct “Črni Kal” is introduced, displacement measurements on the viaduct and an analysis of results, with particular stress on the accuracy of the calculations.