Applied Mechanics and Materials Vols. 584-586

Abstract: Rapid urbanization leads to the contradiction between socioeconomic development and natural ecological system becoming more acute. The planners need to think seriously about these problems: how to scientifically and reasonably plan space layout under macroscopic scale, how to coordinate the relationship between the land and ecological environment and how to promote the healthy and sustainable urban development. This paper takes the concept of anti-planning as the starting point and discusses the construction mode of ecological infrastructure in macroscopic planning. It can provide reference design ideas and methods for urban planning in a macroscopic level.

Abstract: Mixed scanning method is one of the main methods of modern city planning, it considers both the whole and the key. Mixed scanning method is especially suitable for. The study on the relationship between Gongqing DigiEcoCity Gongqing city. Gongqing city is the background of Gongqing DigiEcoCity whose planning must be based on overall framework of Gongqing city, so that economic and social development has complementary effect, and achieve a win-win situation.

Abstract: In modern urban developing process, due to the influence and restriction of historic and economic factors, many historic districts are facing problems such as lack of widespread traditional style building conservation, poor micro-climate conditions, and low living comfort level and so on. Under the trend of increasing attention to the protection of the historic district’s traditional style, the poor micro-climate living conditions fail to be significantly improved. Therefore how to properly combine protecting the historic district’s traditional style and improving the micro-climate becomes a serious problem to be solved, so as to achieve the aim of keeping the historic district’s traditional style and stimulating the vitality of the micro-climate environment. This paper takes the case of Xi’an Sanxuejie Historic District, and studies possible solutions to integrate traditional style’s protection and improvement of micro-climate. Through fieldwork and data collection, the author provides suitable micro-climate improving methods for the traditional courtyard. The purpose is to offer new methods to achieve sustainable development of historic districts.

Abstract: Concrete structures are exposed to carbonation that may cause rapid decay, shortening their service life and raising maintenance and repair costs. Carbonation lowers the alkalinity of the concrete depassivating the steel reinforcement. The prescriptive methodology is not a guarantee to obtain the desired service lives of 50 or 100 years. Surface treatment is commonly used to improve the resistance of concrete to carbonation. Using the silicone materials to an immersion treatment can effectively block the invasion of harmful substances,the carbonation of concretes with surface protection with silicone materials was evaluated. The results showed silicone can lower carbonation depth than the non-protected concretes. The carbonation depth will not increase significantly in the latter part of the concrete service.

Abstract: This paper presents development length comparison between Chinese and Australian codes study on HRB500 steel bars in concrete. After introducing the existing code provisions about the anchorage length and experimental investigation of tensile HRB500 steel bars, the calculation approaches in different codes are compared with the test data. Additionally, the development length of tensile HRB500 reinforcement bars in AS3600-2001, Proposed Revision of AS3600, GB50010-2010 and the calculation equation proposed from test results are compared with each other in beams and slabs. It is proved that AS3600-2001 is inconsistent with other standards and the tests results and needs to be revised, while the Proposed Revision of AS3600 provided a good agreement with the test data and brings the code into line with other international codes, particularly Eurocode 2. Moreover, the Proposed Revision of AS3600 is a significant improvement on the method in AS3600-2001. The anchorage length formula in GB50010-2010 can still be used for designing HRB500 steel bar.

Abstract: The X ray computed tomography (X-CT) was applied to test the cracking resistance of cement paste, and the hydration process was monitored to study the effect of fly ash on the early age cracking performance. The results showed that the hydration heat reduced with the increase of fly ash under the same water-cement ratio. Within 24h, the porosity increased with time. The addition of fly ash increased the proportion of large holes and then changed the internal stress state. Using X-CT test method and by comparing the number of cracks, the sample with 20% FA was found to have the most serious cracks, whereas the sample with 30% FA had the best crack resistance.

Abstract: In order to research the influence of the shear capacity of reinforced concrete beam with the incorporation of basalt fiber, four basalt fiber reinforced concrete beams with parameters of length and volume ratio were designed and made. The fiber lengths were 12mm and 30mm, and the volume ratios were 1‰ and 2‰. The test data of basalt fiber reinforced concrete was obtained through the shear experiments and comparison with the common reinforced concrete beam. The results of the experiment show that the cracking load of the basalt fiber reinforced concrete beam increase obviously with the growing of fiber characteristic parameters, and effectively reduce the diagonal crack width.

Abstract: A dynamic spherical cracked-comminuted response model was proposed for the penetration into confined concrete targets with finite radius and lateral elastic confinement. The material was described by linear pressure-volumetric strain relation and Griffith strength theory in the comminuted region, and described as incompressible in the cracked region. Numerical results show that the cracked-comminuted interface velocity and the cavity expansion stress increase with the increase of cavity expansion velocity, the ratio of targets radius to comminuted region radius and the lateral confining rigidity.

Abstract: The flexural behavior of concrete beams strengthened with near surface mounted (NSM) CFRP-PCPs composite rebars was studied. Experimental results showed that embedded CFRP-PCPs reinforcement method can effectively improve strength, stiffness and cracks of the reinforced concrete member, and PCPs increased with concrete bonding area, thus avoiding the strip damage of the traditional embedded reinforcement.

Abstract: elliptical Concrete-filled steel tubular (ECFT) columns are often used as the main supporting columns for high-rise buildings and has become a topic of academic concern. The past research about ECFT most focused on its ultimate strength and mechanical behavior. The experiment method which is usually expensive and time-consuming. Other research methods include combining experimental data with appropriate theory to design or calculate the structural properties, and these methods tend to have a conservative assessment of the results. Therefore, some researches have been developing finite element model to simulate and analyze the ultimate strength and buckling condition of ECFT and its component behavior. In this paper, finite element analysis is used to explore the mechanical behavior of ECFT during exerting axial compression load. Contact pair settings and friction coefficient settings were compared with different pattern to investigate the accuracy of simulation and the mechanical behavior of ECFT columns. Study found that the ultimate strength for ECFT columns obtained by finite element analysis can achieve good accuracy, and in the meantime the mechanical behavior simulation of ECFT columns with proper finite element settings could be achieved.