Advanced Materials Research Vol. 742

Abstract: Not collapse under strong earthquake is an important goal of the seismic design of reinforced concrete structure, seismic collapse resistance performance is directly affected by the deformation behavior of reinforced concrete column. The application of high-strength steel, high-strength stirrup and high-strength concrete can enhance the concrete material properties and mechanical properties of reinforced concrete column, but their deformation behavior have large differences. The research on the seismic performance of columns with high-strength materials, especially its deformation behavior, become the most important issue of anti-collapse analysis. In this paper, the ultimate displacement angle of concrete columns with high-strength materials were collected, the ultimate displacement angle and inter-story drift angle 1/50 were compared and analyzed. The results show that the average of ultimate displacement angle of the reinforced concrete column with high-strength stirrup and high-strength longitudinal bars are 0.0469, 0.0312, respectively, greater than inter-story drift angle 1/50, while the average of ultimate displacement angle with high-strength concrete and high-strength core concrete are 0.0147, 0.0167, less than 1/50, therefore, it is not suitable for taking 1/50 as the critical value of structure collapse with high-strength concrete. The inter-story drift angle should be different in the anti-collapse analysis.

Abstract: In order to strengthen the co-work performance between the steel plate and concrete, the anchorage construction of arrayed studs were welded on both sides of the plate according to a super high-rise building in Beijing. Eighteen specimens of embedded steel plate concrete shear walls with arrayed studs were tested by pushing out under monotonic loading in this paper. Some parameters, such as the thickness of the concrete wall, the thickness of steel plate, the diameter, the length and the amount of the studs and the rate of reinforcement for distributing bars in the walls were considered. The shear bearing capacity, load-slip relationship, strains of the steel plate and studs, mechanical properties and failure mode were analyzed. The effect of stud layout on the coordinate work of the concrete plate was studied. Results show that the shear bearing capacity is obviously improved by using smaller diameter studs or decreasing the distance between studs when the total area of studs is kept unchanged. The thickness of the steel plate has almost no effect on the shear bearing capacity. The ratio of the length to the diameter of the studs should be not less than 4. A simplified mechanics calculated method to estimate the shear bearing capacity of this kind of shear wall was put forward. And the calculated results are in good agreement with the experimental results.

Abstract: There are mainly two approaches to improve the fire resistance of FRP systems. While the most common way is to protect or insulate the FRP systems, the other way is to use fibers and resins with better fire-performance. In this paper a numerical investigation for evaluating the fire behavior of insulated CFRP-strengthened RC beams is presented.The effects of external loading and thermal expansion of materials in both the structural and the thermal behavior of composite elements due to loading and elevated temperatures are taken into consideration in a finite element model. The validity of the numerical model isdemonstrated withthe results from an existing experimental study on insulated CFRP-strengthened RC beam. The conclusions of this investigation have been employed to predict the structural behavior of concrete structures successfully.

Abstract: Aluminium alloys are nonlinear metallic materials with continuous stress-strain curves that are not well represented by the simplified elastic, perfectly plastic material model used in many current design specifications. Departing from current practice, the continuous strength method (CSM) is a recently proposed design approach for non-slender aluminium alloy structures with consideration of strain hardening. The CSM is deformation based and employs a base curve to define a continuous relationship between cross-section slenderness and deformation capacity. This paper explains the background and the two key components - (1) the base curve and (2) the strain hardening material model of the continuous strength method. More than 500 test results are used to verify the continuous strength methodas an accurate and consistent design method for aluminium alloy structures.

Abstract: On the requirement of evaluating the bearing capacity of corroded reinforced concrete lock-walls servicing on the Yellow River, the experimental study was conducted to investigate the loading behaviours of normal section of lock-walls, which considered the changes of concrete strength and corrosion level of rebar. The rebar corrosion was accelerated by the mixing of sodium chloride (NaCl) into concrete and the electrolyte corrosion technique in condition of dry-wet curing. The vertical eccentric load was applied on the top of the wall. The results show that some horizontal cracks firstly appeared on the surface of walls during the corrosion period and became wider under the vertical load on the wall. The typical ultimate state was flexural failure. The effects of concrete strength and rebar corrosion level on the resistance of normal section are analyzed based on the test data.

Abstract: Proposed EPS beads for the improvement of expansive soil in cold regions. Based on laboratory soil test study the feasibility and mechanism of the EPS beads improving expansive soils. Through four sets of comparative test with different contents of the EPS beads, the result indicates: The expansion rate of the soil, frost heave amount decreases with the increase in EPS beads content, EPS beads can effectively inhibit the expansion of expansive soil and frost heaving, proposed the optimal dosage.

Abstract: Research on rutting deformation was performed using a wheel tracking machine (WTM) in the laboratory. The limited capabilities of the equipment, which can run for 1,260 cycles, are often an obstacle to accomplishing more in-depth analysis. This study evaluated the use of two types of asphalt mixtures based on the penetration value and the temperatures. The goal of this study was to use the WTM at a short cycle capacity to collect up to 3,780 cycles to reach plastic deformation (secondary zone). The curve is not continuous due to the lag time between each step of the test. The model was developed based on the changes in the deformation for each cycle. A method is proposed to evaluate the relationship between the rutting deformation curve and the load cycles of WTM during testing. The results showed that the curve is the power function with R² values from 0.963 to 1.000. This model can improve the shape of the curve with the addition of a reload step in the WTM short cycle.

Abstract: The coconut fiber presents higher ductile properties than other natural fibers. In previous studies, it demonstrated than Indonesian coconut fibers presents an improved tensile strength and failure strain after washed with water and dried. The coconut fibers have the potential to reinforce material for construction, especially in earthquake areas such as tropical countries. The purpose of this research is to assess the benefit brought by coconut fibers content on the tensile behavior of mortar composite. Splitting tensile strengths were measured and microstructure observed using scanning electron microscopy (SEM). The influence of fiber content (expressed by a mass ratio fiber/cement) is investigated. The results show that a fiber content of 5% allows a 10 times higher deflection and presents a 1.5 times higher tensile strength than mortar without fiber. Further studies will focus on the bond strength between the fiber and the cement mortar matrix.

Abstract: This research paper is an effort to highlight prominent key risks which are involved in marketing of civil engineering products. Construction moguls hire the services of third party to market and sale the engineering products but they are not fully experts in construction affairs. A framework of marketing risks has been devised to help the third party personnel during sales of completed or under process civil projects. These risks have been evaluated by the sales managers and site engineers through survey process. Last three decades have witnessed the Chinese economy growing at very rapid rate especially for massive construction developments. Rapid developments in building designs, customers ever changing demands, state policies and geographical locations have made the marketing strategies risk prone in China. Marketing concept was introduced during 60s to get the cmpettive advanteges by business moguls. His concepts caused a paradigm shift in business concept to suggests that business should satisfy their customers needs which are the heart of business. Customers loyalty and satisfaction were put at first in priority. The results indicate that the key risks as: economic slowdown, price inflation, liquidity risks, capital risks, competition, interest rates, land acquisitions, payment risks, investors changes, inaccurate cost estimation, design variations, administrative issues, poor competency of third party, non-familiarity with construction affairs, poor safety measures, political stability, law and order situation and problems for approval and permission process cause to push construction entrepreneurs towards complex scenarios. These results have been extracted on the basis of research survey. 313 paper base and online questionnaires were sent to solicit responses from sales professionals and site engineers during survey. Overall, 113 responses were collected during research survey. Responses were scaled on 5-likert scale. Data has been analyzed using SPSS software.

Abstract: In this paper, pavement roughness is assumed as random stationary variable and used as the exciting force of theoretical analyses of the quarter car model of International Roughness Index (IRI). From the frequency response function of the quarter car, the response function of the displacement difference between sprung and unsprung mass is obtained based on random process theory. Then the relationship between IRI and power spectral density (PSD) is established from statement characteristic of the response function. Finally, the longitudinal road profiles of typical asphalt roads in China are used to validate the proposed model.