International Journal of Civil Engineering
Volume:15 Issue: 5, 2017

This paper tried to analyze the behavior of a typical bridge and the effect of its skew degree on its behavior to near-field earthquakes. To this end, the seismic behavior of a number of typical bridges with same spans and different skew degrees was studied under near-field and far-field earthquakes. Non-linear static analyses (pushover analyses) were performed to determine the performance parameters of the bridge in each model. Non-linear time history dynamic analyses were also performed on the models to analyze the dynamic behavior and deformations of bridge components under near-field and far-field earthquakes. The responses of models, such as their displacement, base shear, and axial forces of columns to earthquakes under study are presented in the following sections. Results indicated that the base shear and displacement of the superstructure in near-field earthquakes without velocity pulse and far-field earthquakes are about or less than the corresponding values of the bridge performance point. Moreover, in the case of near-field earthquakes with velocity pulses the values of these parameters showed an increase. It was also revealed that an increase in the skew degree of the bridge led to an increase in the axial forces in columns and transverse displacement of the bridge.

Colored self-compacting mortar (C-SCM) is a novel cementitious product that has been recently used in decoration and rehabilitation and has improved esthetic quality of architectural constructions. C-SCM is susceptible to strength decrease due to excessive pigment presence in the mixture. Optimum pigment content with respect to color intensity and mechanical performance is an important matter that should be determined to prevent mortar failure after construction. In this research, two inorganic pigments in production of colored self-compacting mortar were utilized. The impact of titanium dioxide (TiO2) and iron hydroxide (FeO(OH)) contents on behavior of C-SCMs was investigated in white and gray cement matrixes. Experiments included measurements of compressive strength of mortar cubes and cylinders, flexural strength and colorimetric properties. Analyses on compressive and flexural toughness were applied, as well. It was concluded that pigment content in mix design of colored self-compacting mortar could be optimized with regard to color quality in surface and mechanical strength of the product. Results implied that 5 and 2% of titanium dioxide were the saturation points of color and strength, respectively, and iron hydroxide at 10% was unsurpassed in C-SCMs containing white cement. Application of both pigments in gray SCMs caused the saturation points of color and strength to occur at 10 and 2%, respectively.

One of the main concerns in an essential or highly important building is finding the appropriate structural system, while the efficiency of each conventional structural system varies in different cases. In this paper, a new multi-objective structural configuration is proposed and its efficiency for protecting buildings against the multi-hazards, including earthquake, explosion, and typhoon, is shown in a case study of a 10-story building sample. To create the optimum and efficient configuration of the structural elements, and to make some large spans, a configuration including Vierendeel girders is used. In this type of configuration, the inner suspended floor parts protect the outer elements by balancing perimeter span loads. This system makes a new condition for the building to be protected against the progressive collapse due to the terrorist attacks. Furthermore, the partially suspended floors in special stories act like tuned mass dampers (TMDs), which are suitable to decrease the amplitude of the displacement response of the structure during an earthquake.

There are challenges and opportunities of deploying policies for transport infrastructure improvement in developing countries. Transport infrastructural development remains a major tool for achieving the aspirations of the newly introduced economic principles of the Federal Government of Nigeria. This study investigates the impact of innovative strategic approaches for improved transport policy and how the strategies are well incorporated to solve the problems faced in the infrastructure sector to enhance improved economic growth. The research involves a questionnaire survey conducted to key stakeholders in Nigerian six states. The study was focused on the stakeholders selected from the public entities, private clients, consultants, and contractors operating within the Nigerian construction sector. Based on the empirical data, the specific ways in which innovative strategies for transport policies affect infrastructure development contributing to sustainable economic growth have been shown. The findings contribute to the fields of innovative strategies for transport policies in infrastructure development by linking various aspects of innovative strategies for transport policies and infrastructure development and their interrelationships to sustainable economic development from stakeholders’ perspective. The results show that variables of innovative strategies in transportation and transportation infrastructure improvement have different roles and significant positive impact on sustainable economic development.

Local scour downstream of hydraulic structures is one of the critical phenomena, which has absorbed a vast amount of interests by researchers. The designers of hydraulic structures, particularly, spillways try to utilize proper means to minimize the consequences of excess energies downstream of such structures which usually tend to erode their immediate downstream reaches. The stepped spillway is designed to create a large amount of energy losses by action of its steps to lessen the amount of scour evolution at its immediate downstream. This article presents the results of 67 experiments conducted at two different scales of stepped spillways, to study the local scour downstream of the structure. The experiments were planned to consider a wide range of geometrical factors, flow characteristics, and sediment properties. The time duration of experiments was ranged from 6 to 24 h which produced more than 80000 data points for analytical considerations. The results were used to render some regression equations to define the similarity among the scour hole profile and its geometrical characteristics. It was observed that a long-term observation would be required to reach the equilibrium state. However, semi-equilibrium conditions will be achieved some times after 24 h. It was also noted that the depth of scour hole adjacent to channel walls was bigger than that of centerline. Finally, it was realized that the stepped spillway causes energy dissipation between 42.06 and 74.82% which results in a shallower scour hole compared to ogee spillways.

For years, coupled shear walls have been used in the mid-rise to-high-rise buildings as a part of lateral load resisting system, mostly because of their ability to control the displacement of structures. Recently, by changing the concept of design codes from strength-based to performance-based, assessment of nonlinear behavior of coupled walls became important for engineers. Therefore, many researchers now are looking for ways to improve and also predict the behavior of coupled walls under severe earthquakes. This paper presents the results of linear, nonlinear static (pushover), and nonlinear inelastic time-history analyses of a 10-story structure with two-dimensional coupled shear walls (CSW) which are perforated using three different patterns taken from considering the S22 stress of shell elements of shear walls. Nonlinear static analysis results confirm that perforation can increase the response modification factor of coupled walls up to 33 percent. In addition, the results of linear analysis and design indicate that perforation can reduce the required reinforcement of coupling beams and other frame’s structural components. In addition, results of nonlinear inelastic time-history analysis confirm that, using perforation patterns, the base shear—roof displacement hysteretic response improves and the systems with perforation patterns can absorb more energy under severe earthquakes.

Fiber-reinforcement concrete is mainly distinguished in their behavior in cracked tension zone which is called tension softening behavior. Wide researchers have been investigating this behavior and presented many tensioned softening models, whereas these models have not been compared together. This paper presents a compression between four tension softening models including constant, linear, bilinear and exponential models in flexural behavior. Comparison of these models has been done in flexural behavior of rectangular section. In this study the behavior of rectangular beam section under four/three point bending test have been predicted by iteration procedure. These models have been compared in some parametrical properties and also with some existing experimental data. Although models have unique fracture energy, the result of this study shows variety in result including peak load, area under load–deflection for used models. It presents that this method cannot be used for meaningful comparison and indicates concern in applied assumption that was referred in many papers.

Among important issues in progressive collapse behavior of a building is tracking down the type and location of the damaged elements. This paper deals with the distribution of 3D collapse from the first element to the entire symmetric and asymmetric RC buildings due to earthquake loads. The variables of such analyses are earthquake load intensity and the value of one directional mass eccentricity. Results show that the collapse propagation is dependent on the degree of asymmetry in building. Some patterns are also determined to predict the progressive collapse scenarios in similar symmetric and asymmetric buildings. Patterns show that the propagation of collapse is horizontal through the stories, but not vertical through the height of the buildings. Spread of the collapse is independent of the earthquake records and damage concentration is larger in places with larger mass concentration.

This study utilized telematics technology to automatically collect data that could then be used to improve striping performance without the need for additional staff or equipment. This paper presents the telematics data collection and implementation in two areas: (1) providing performance analyses using telematics data and (2) developing performance metrics for future performance measurement. Striping is a continuous maintenance operation for all roadway O&M managers and it requires substantial resources and financial investment if good or excellent striping condition is to be maintained. Striping mileage per day was used to represent productivity in this study. The average striping mileage in 2012 comprised only 15–25% of the total average driving miles per day. The utilization analysis indicated that centerline trucks were utilized at significantly higher levels than edgeline trucks, although the overall utilization ratio only ranged between 20 and 30%. Three levels of productivity metrics were developed from normal distribution probability density functions and appropriate parameters obtained from the Monte Carlo simulation results. Measured in terms of striping miles per day, low productivity was taken to be any value less than or equal to 30%, medium productivity any value more than 30% and less than or equal to 70%, and high productivity any value over 70%. As a result of the study, performance analyses revealed that there was sufficient room for improvement and several recommendations were made. Multiple operational scenarios reveal that productivity and utilization can be increased up to 47 percent while eliminating several striping trucks. Performance metrics were provided using Monte Carlo and triangular distribution.

Prediction of compressive strength by a proper model is a fast and cost-effective way for evaluating cement quality under various curing conditions. In this paper, a logarithmic model based on the results of an experimental work conducted to investigate the effects of curing time and temperature on the compressive strength development of chemically activated high phosphorus slag content cement has been presented. This model is in terms of curing time and temperature as independent variables and compressive strength as dependent variable. For this purpose, mortar specimens were prepared from 80 wt.% phosphorus slag, 14 wt.% Portland cement, and 6 wt.% compound chemical activator at Blaine fineness of 303 m2/kg. The specimens were cured in lime-saturated water under temperatures of 25, 45, 65, 85, and 100 °C in oven. The model has two adjustable parameters for various curing times and temperatures. Modeling has been done by applying dimensionless insight. The proposed model can efficiently predict the compressive strength of this type of high phosphorus slag cement with an average relative error of less than 4%.