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An extensive and varied usage of optical fibers is found widely in all the engineering sectors. This paper aims at providing a feasible solution for measuring the stress applied on the reinforced concrete slab using an optical fiber. An MSP430 board is used as the signal conditioning circuit to calibrate the sensed pressure and the same also employs a clever strategy to log the data in standalone...
The article introduces the results of using the infrared radiometry method for qualitative evaluation of stress-strain state in different parts of the rock mass at Tashtagol mine.
We report on long-term measurement results on post-tensioned concrete specimens. A total number of 8 specimens, each of dimensions 700×150×150mm3 and four each of two different concrete mix designs, are subjected to prestress by post-tensioning iron bars conducted in a central longitudinal hole. During their drying phase the specimens undergo a prestress loss from creep and shrinkage, resulting in...
An optical fiber sensor system that can be installed and used to give reliable and informative data has been developed, tested and evaluated for the past two years on a 50 year-old concrete foot bridge of known conditions. Besides environmental monitoring, the bridge has been subjected to different loading and specific damages have been induced. The evolution of the bridge has been recorded using...
This article discuss firstly the research and practice of temperature control technology of massive concrete in large-scale cushion cap in Baishazhou Yangtze bridge at Wuhan and Sutong bridge, then demonstrates that the using of screen optimization of raw materials and mix proportion, scientific planning of pouring technology, reasonable select of maintenance, and application of monitoring in real-time...
The hollow pint-sized concrete block is a kind of new energy-saving material for wall. In the popularization process under difference in temperature, the crack of the concrete small hollow bloc is the general problems. Masonry wall temperature load calculation, mainly is the temperature difference formula. In the calculation of masonry structure, not only should consider experience for a short time,...
For the reliable assessment of bridge health and safety conditions, it is important to distinguish the abnormal changes of bridge structural responses caused by structural damage from the normal changes due to environmental fluctuations. This paper addresses the modeling of separating temperature effect from structural strain responses of a tied arch bridge in China. The bridge has been instrumented...
In this paper the thermal expansion coefficient of high strength/performance concrete with water-cement ratio of 0.3 at early ages was measured more accurately by improving Yang Yang proposed method previously, in which the temperature change was given to concrete specimens in a lower temperature region from −1 to 5°C. The results showed that a good linear relationship exists between the strain and...
Generally, the concrete whose intensity level is C60 and above is called as high-strength concrete. High-strength concrete is usually used for vertical pressure component due to its poor ductility and its advantages of high compressive strength, good fluidity, denseness, low porosity, etc. Combined with engineering examples, monitoring was conducted for the strain on the binding site of high-strength...
An investigation of deformation properties of square concrete columns confined with CFRP sheets at low temperatures were carried out experimentally. The experimental results showed that the CFRP sheets can increase the bearing and deformation capacity of concrete columns effectively at low temperatures. And the experimental curves show that area of plastic deformation increases, the curves become...
This article based on the practical engineering, using the finite element analysis method to analysis temperature effect on over-long floor without expansion joint on the condition of different temperature load, draw a conclusion of temperature stress distribution and magnitude by the consideration of concrete shrinking stress, geometrical non-linearity etc.
High performance concrete (HPC) is one of the vital materials in civil engineering field throughout the world for its high strength, high durability and low permeability etc. while due to its relative low water cement ratio and the use of mineral admixtures, it may develop considerable AS (autogenous shrinkage) due to self-desiccation at early age compared to ordinary concrete. The pretty higher AS...
The concrete small hollow block is a kind of new energy-saving material for infilled wall, but in the popularization process the crack of the concrete small hollow bloc is the common problems. cracks of infilled walls of frames were the main object of study in the paper and crack mechanism of the single wall and the whole structure were studied respectively on based of the investigation in full. Then...
High-performance slag concrete is more likely to cause the emergence of crack than common concrete. In view of this problem, this paper introduces the forming mechanism of crack in concrete structure and puts forward the corresponding measures and methods. Generally speaking, the internal and external temperature difference at early stage and the basic difference of temperature at later stage are...
An improved form of basic genetic algorithm: Niche genetic algorithm which is based on sharing function is designed. It is aiming at the premature problem of basic genetic algorithm that existed in the back analysis of parameters of concrete thermal field. According to the measured temperature of concrete of rock anchor beam during construction period, its program composition is used to carry out...
In the light of the temperature crack problem of the construction of RCCD during cold winter season, the authors have analyzed the dam cracking site and the cracking mechanism. Pointed out that the early autogenous volume deformation and temperature difference between inside and outside of the bedding concrete and the temperature difference of basis concrete are the main reasons resulted in the crack...
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