temperature, humidity and wind play a vital role in the quality and strength of hardened concrete. The following points must be ensured at site to produce the concrete of required strength: 1. In order to achieve full compaction and maximum density, it is necessary to use a mix with adequate workability. 2. To obtain maximum strength of the concrete a driest possible concrete should be produced and shall be compacted 100 %.
For example strain hardening, as the ductile material is deformed more and more its strength and its hardness increases because of the generation of more and more dislocations, so, in engineering applications, especially the ones which have safety concerns involved, ductile materials are the obvious choice. Safety and dependability are the main concern in a material design, but in order to attain these goals, there needs to be a thorough understanding of the fracture both brittle and ductile. Understanding fracture and failure of materials will lead the materials engineer to develop a safer and more dependable materials and
1. structural factor which happen because of shape size or the choice of materials, or due to the geometry design, or manufacture error or the improper materials and this type of failure occurs usually in a weak point of errors like edges or corners. 2. Performance factor. Cause usually the factors lead to building collapse regardless the natural reasons are a human error so it might have found some weak points in any building. Reasons why building fall down 1.
Elasto-Plastic Seismic response of RC continuos bridge with foundation-pier dynamic interaction (Bo, Chen, Yu) 2015,18, 6, Advances In Structural Engineering Using materials with high quality can help the bridge strengthen its durability. In this article, the shallow foundation is often employed as the base for bridges. And due to some natural phenomenon, the shallow foundation experiences plastics deformation. No matter how durable the strength of matrials used in building up brides, if the very own foundation is not strong, the bridge itself is not strong enough to withstand some phenomenons. This article shows that the study of soil-structure interaction (SSI) will help to maintain a proper foundation for bridges.
Assignment 2 CVE80006 Infrastructure Deterioration Modelling Concrete Crack Diagnosis Assignment The phenomenon of cracking in concrete may depend on several factors such as the amount of loading, rate of bleeding, amount of stress and strain generated in concrete, the composition of concrete and method of fabrication. The cracking of concrete has become severe due to advance construction process which demands high strength structure requiring an increase in stress, strain, and deflection resistance. The cracks in concrete are mainly classified as structural crack and non-structural crack. Structural Crack - Shear Crack and Extra Compression Loading Crack Figure 1. Shear Crack Figure 1 is an example of shear crack found at Swinburne
Shrinkable soils Foundation failure due Settlement of Soil Fill If the building is made on a newly area by soil filling, the foundation here on such soils take more and more time to settle . As long time is needed for such soil to settle and become compact to resist the loads from the building foundation. 3.2 Causes of failure due to seepage: Seepage should be controlled in both velocity and quantity. If it is difficult to control the seepage, it can erode soil from its foundation, resulting in failure of the dam which means the failure of a lot.. Erosion of the soil starts at the downstream side.
DURABILITY Structural durability is the capacity of structures to resist deterioration given expected and unexpected environmental attack. The aim is to maintain the potential of serviceability loss and structural failure at an acceptable level throughout a specified service life. The improvement of structural durability requires an understanding of environmental exposure, which may be significantly affected by climate change-related factors such as increasing concentrations of atmospheric CO2, rising air temperatures, and sea level rise. Practices to reduce deterioration should be considered at four stages: material design, structural design, construction, and operation. In general, the standards address the need to take into account the
In this section, basic components of a damage-plasticity model for the concrete material are shortly discussed and detailed investigation of it is provided in Appendix A. A damage-plasticity model can be formulated in terms of either effective or nominal stress. However, according to the local uniqueness condition in which a specific strain history results in a unique stress and internal hardening variables response (refer to Grassl and Jirasek ), damage-plasticity models formulated in terms of effective stress space are preferred in this study. Furthermore, these types of damage-plasticity models result in a simpler stress-updating algorithm. The material model used in this study is according to the Grassl et al.
Concrete is weak in tension, and for normal strength concrete, tensile strength is only 10% of its compressive strength and for High strength concrete tensile strength ratio is further reduced. Thus, tensile strength of concrete is often neglected in strength calculations. However, it is an important property, because cracking in concrete is generally due to tensile stresses and the structural damage of the member in tension is often generated by progression in microcracking in thermal expansion coefficients between the aggregate and cement paste and decomposition of calcium hydroxide. At temperatures above 450˚C concrete compressive strength drops significantly due to loss of bond between the aggregate and cement paste. Under fire conditions tensile strength of concrete can be even more crucial in cases where fire induced spalling occurs in a concrete structural member.
CHAPTER 1 INTRODUCTION 1.1 GENERAL Concrete made with Portland cement has certain characteristics: Concrete relatively strong in compression where as weak in tension and tends to be brittle. Another reason behind weakness of the concrete is that cracks start to form when concrete is placed and before it gets fully hardened. The cracks are major factor of weakness in concrete in large onsite applications leading to subsequent failure, generally lack of durability and fracture. The weakness in tension of concrete can be overcome by the use of conventional steel bar reinforcement and to some inclusion of a sufficient volume of fibers. Polypropylene (PP) is made by synthetic hydrocarbon polymers which are extracted by the processes of hot drawing