Glass Columns under Impact - Experimental and Numerical Analyses

2017 ◽  
Vol 755 ◽  
pp. 82-89
Author(s):  
Chiara Bedon ◽  
Roman Kalamar ◽  
Martina Eliášová

Compared to traditional construction materials, structural glass members subjected to main compression are relatively unusual in buildings, despite a substantially high material compressive strength. The major limit for the use of glass columns is in fact represented by an overall residual load-bearing capacity highly affected by the tensile brittle fracture of glass. An optimal and fail-safe design approach, in this regard, should take care of a multitude of geometrical and mechanical aspects, including boundary details and possible defects, as well as accidental loading scenarios. Aiming to assess the feasibility and vulnerability of structural glass members, based on earlier research efforts, the paper deals on the load-bearing performance of a reference set of full-scale glass columns. Careful consideration is in fact paid for the experimental investigation of glass members with square hollow cross-section and subjected to dynamic impacts, being representative of an accidental loading scenario. Full-scale experimental results are presented, as well as further considered for validation and calibration of Finite Element (FE) numerical models accounting for possible damage propagation in all the structural components, hence allowing to assess the residual load-bearing capacity of the examined structural typology.

Author(s):  
I. Rybnikova ◽  
A. Rybnikov

Three methods for determining the load-bearing capacity of bored conical piles are presented, considering the additional forces of the ground rebound along their inclined side surface under vertical load. It is proposed to determine the bearing capacity according to the results of field tests using the coefficient of transition from the maximum permissible settlement of the building foundation to the settlement of the pile obtained during static tests. Its value varies from 0.1 to 0.3 depending on the angle of the pile taper. To determine the bearing capacity of the empirical method, tabular data of the ground rebound forces on the side surface of the piles are developed. It depends on the strength properties of the base soil, the angle of the pile taper and the depth of the location of the changing cross-section of the pile along the length. The process of compressing the soil in a drilled well with an elastic cylindrical pressiometer is close to the occurrence of a ground rebound when it is pushed apart by the side surface of a conical pile during sediment under load. It is proposed to determine the ground resistance on the side surface of conical piles according to the same dependence as when processing the results of pressiometric tests of soils, taking into account the introduction of a correction factor depending on the parameters of the pile. The calculated load-bearing capacity of the piles, determined by the proposed methods, differs from the actual load-bearing capacity, determined by the results of static tests of full-scale piles, within 10 %. However, these methods need to be improved with the accumulation of statistical data for testing full-scale piles in different ground conditions.


Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5463
Author(s):  
Guangyuan Fu ◽  
Gongyi Fu ◽  
Siping Li ◽  
Jian Yang ◽  
Feiliang Wang

Previous studies have shown that components with an unequal-walled concrete-filled rectangular hollow section (CFRHS) can achieve a greater resistance under bending than those with equal-walled CFRHS. However, the study on the compressive behavior of the CFRHS column is limited. Therefore, this paper investigates the performance of compressed CFRHS columns with unequal flange thickness, based on experimental and numerical approaches. In the test, the effects of slenderness and eccentricity on the compressive capacity of the CFRHS columns with unequal shell thickness are discussed. Numerical models based on the finite element method are established, to evaluate the resistance and failure pattern of each specimen in the test. Parametric studies are carried out based on the validated model, to investigate the effect of eccentricity, wall thickness, and steel and concrete material properties on the load-bearing capacity of the compressed CFRHS column. In addition, the analytical expressions of the resistance of CFRHS columns with unequal wall thickness are derived, and the prediction values are validated through comparing with the test results. It is found that eccentric compressed columns with unequal-walled CFRHS have a similar load-bearing capacity and better ductility when compared with the equal-walled CFRHS.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1160
Author(s):  
Janusz Brol ◽  
Jan Kubica ◽  
Marek Węglorz

This paper presents a discussion of the problem of compressive strength in a direction perpendicular to the grains based on test results of the joints made by timber posts and sill plate. These tests accompanied a larger series of full-scale tests of timber frame walls. The test elements were made of solid softwood (spruce). The wood moisture was low, which corresponds to the real working conditions of these elements in the walls of a building (low humidity is typical for dry wood in the built-in wall of a real building). In the tests, the compression strength of timber perpendicular to the grain was exceeded in the sill plate in the area in contact with the posts. Shortly before reaching the state of failure, large displacements in the sill plate were measured on the contact surface with the post, and the grains in the sill plates were cut off at the edge of the post. The full-scale test results showed an overestimation of the load-bearing capacity in compression perpendicular to the grain when calculated on the basis of EN 1995-1-1+A1:2008 (Eurocode 5), and, therefore, the need to modify the current approach for determining it.


Author(s):  
Krisztián Andor ◽  
András Lengyel ◽  
Rudolf Polgár ◽  
Tamás Fodor ◽  
Zsolt Karácsonyi

Enhancement of structural behaviour of various construction materials using fibre reinforced plastics (FRP) is an important branch of engineering research, including the increasing application for structural timber as well. This study deals with the reinforcement of standard construction formwork timber beams with carbon fibre reinforced plastics (CFRP). Beams with various amount of reinforcement were prepared using simultaneous formation of lamella and bonding. Laboratory bending tests are carried out and load-deflection data were measured to experimentally determine the change of load-bearing capacity and stiffness with respect to non-reinforced reference sample, as well as to assess the structural behaviour. Evaluation of failure modes is carried out on each specimen. A statistical analysis of the experimental results using t-test is also made. The experiments prove the enhancement of structural behaviour, especially in terms of the increased load-bearing capacity, the increased ductility in certain cases, the decrease of the scattering of results, and also in failure modes.


2020 ◽  
Vol 62 (1) ◽  
pp. 55-60
Author(s):  
Per Heyser ◽  
Vadim Sartisson ◽  
Gerson Meschut ◽  
Marcel Droß ◽  
Klaus Dröder

2017 ◽  
Vol 68 (1) ◽  
pp. 94-100
Author(s):  
Oana Tanculescu ◽  
Adrian Doloca ◽  
Raluca Maria Vieriu ◽  
Florentina Mocanu ◽  
Gabriela Ifteni ◽  
...  

The load-bearing capacity and fracture pattern of direct inlay-retained FRC FDPs with two different cross-sectional designs of the ponticwere tested. The aim of the study was to evaluate a new fibre disposition. Two types of composites, Filtek Bulk Fill Posterior Restorative and Filtek Z250 (3M/ESPE, St. Paul, MN, USA), and one braided polyethylene fibre, Construct (Kerr, USA) were used. The results of the study suggested that the new tested disposition of the fibres prevented in some extend the delamination of the composite on buccal and facial sides of the pontic and increased the load-bearing capacity of the bridges.


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