In recent years, environmental protection is increasingly becoming a major issue in transportation including asphalt production. Despite the fact that Hot Mix Asphalt (HMA) is widely used around the world some recent studies suggest using Warm Mix Asphalt (WMA) technology that reduces the production and placement temperature of asphalt mixes. Currently, a common way of producing WMA is through the utilization of additives. This paper firstly characterizes the effect of WMA additives (organic, chemical, water containing additives) on base bitumen properties. Following the determination of optimum bitumen content of the mixtures with different WMA additives through Marshall Test, Hamburg Wheel Tracking Device is used to measure the permanent deformation characteristics of WMA mixtures. Based on the findings of this study, the utilization of WMA additives help in the reduction of viscosity values which are in return decreases mixing and compaction temperature leading to the reduction of energy costs as well as emissions. Besides, it can be concluded that all WMA mixtures performed better than HMA mixtures in the matter of rut depth.

Sufficient literature is available on approaches to deal with heterogeneous traffic on mid-blocks in developing countries, but not much work is done on roundabouts. The estimation of passenger car unit (PCU) for different vehicles to convert heterogeneous traffic into homogeneous traffic is a well-accepted procedure. But the parameters used for mid-blocks may not be helpful on roundabouts as traffic flow characteristics on the two locations are different. Suggested PCU values on roundabouts from developing countries are not recent, and needs a relook. It is also not clear whether to use static or dynamic PCU values on account of possible temporal and spatial variations across locations. This paper presents an estimation approach for PCUs on roundabouts, as well as, suggests using static value instead of dynamic. The problem to deal with re-estimation of PCU values at different locations, due to possible traffic flow variations, is dealt with by proposing a Heterogeneity Equivalency Factor (H-Factor). The factor is multiplicative and converts heterogeneous traffic (veh/h) into homogeneous traffic (pcu/h).

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 in order 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.

Colored self-compacting mortar (C-SCM) is a novel cementitious product that has been recently used in decoration and rehabilitation and has improved aesthetic 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 were 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.

For years, coupling shear walls have been used in  the mid 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 design codes from strength based design to performance based  design, nonlinear behavior of coupled walls became important for practical engineers, so that many researchers  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 analysis  of a 10-story  two- dimensional coupling shear wall (CSW) which is perforated with 3 different patterns which are taken from considering  the S22 stress of shell elements used for modeling shear walls,  nonlinear static analysis results confirm that perforation can increase the response modification  factor of coupled walls up to 33 percent and also the results of  linear analysis and design indicate that perforation can reduce the amount of reinforcement of coupling beams and other frame's  structural components. Also results of nonlinear inelastic time history  analysis confirm that by using perforation patterns the base shear- roof displacement hysteretic response get better 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 investigated this behavior and present many tensioned softening models. This paper presents a compression between four tension softening models including constant, linear, bilinear and exponential models in flexural behavior. In this study the behavior of rectangular beam section under four/three point bending test have been predicted by iteration procedure. These models has been compared in some parametrical properties. The result of this study shows variety in result for four used models and indicate concern in applied assumptions.

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.

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 the erosion at their immediate downstream reaches. The stepped spillway is designed to create a large amount of energy dissipation by means of steps and would decrease the amount of scour evolution at its downstream. This article presents the results of 67 experiments conducted at two different scales of stepped spillways, to study the local scour downstream the structure. The experiments were planned to consider a wide range of geometrical factors, flow characteristics, and sediment properties. The time length of experiments was ranged from 6 to 24 hours which produced more than 80000 data points for analytical considerations. The results were used to render a regression equation to define the similarity among the scour hole profiles. It was observed that, a long term observation would be needed to reach the equilibrium state. However, semi-equilibrium conditions will be achieved after 24 hours. It was also noted that the depth of scour hole adjacent to channel walls was bigger than that at centerline. 

This paper describes both global and local versions of an energetic analytical model to quantify the damage caused to reinforced concrete (RC) structures under monotonic, cyclic or fatigue loading. The proposed model closely represents the damage to structures and yields a damage index (DI) for the RC members. The model is cumulative and is based on the energy absorbed. The energy under the monotonic envelope curve at the failure of the member is taken as a reference capacity. The data required to apply the model in any given situation or member can be obtained either by numerical simulation or from experimental tests. An analytical computer program was developed to simulate numerically the response of RC members taking into account the nonlinear behavior of the materials and structures involved. The proposed model was verified by comparison with practical tests undertaken by other researchers on over 20 RC columns. The comparison demonstrates that the model provides a realistic estimation of the damage of the RC structural members. The comparison between values of the proposed DI calculated based on experimental test data and numerical simulation results for a cyclic loading case shows that to calculate DI, it is not necessary to perform expensive experimental tests and that using a nonlinear structural analytical simulation is sufficient. The results are also compared to a damage model proposed by Meyer (1988).

Abstract: Rainfall is an important triggering factor influencing the stability of soil slope. Study on some influences of the rainfall on the instability characteristics of unsaturated soil embankment slope has been conducted in this paper. Firstly, based on the effective stress theory of unsaturated soil for single variable, fluid-solid coupling constitutive equations were established. Then, a segment of red clay embankment slope, along a railway from Dazhou to Chengdu, damaged by rainfall, was theoretical and numerical-simulating researched by considering both the runoff-underground seepage and the fluid-solid coupling. The failure characteristics of the embankment slope and the numerical simulation results were in excellent agreement. In the end, a sensitivity analysis of the key factors influencing the slope stability subjected to rainfall was performed with emphasis on damage depth as well as infiltration rainfall depth. From the analysis in this paper, it was concluded that the intensity of rainfall, rainfall duration and long-term strength of soil have most effect on slope stability when subjected to rainfall. These results suggest that the numerical simulation can be used for practical applications.

This paper presents numerical and theoretical studies on the stability of shallow shield tunnel face found in cohesive-frictional soil. The minimum limit support pressure was determined by superposition method; it was calculated by multiplying soil cohesion, surcharge load, and soil weight by their corresponding coefficients. The varying characteristics of these coefficients with soil friction angle and tunnel cover-to-diameter ratio were obtained by wedge model and numerical simulation. The face stability of shallow shield tunnel with seepage was studied by deformation and seepage coupled numerical simulation; the constitutive model used in the analysis was elastic-perfectly plastic Mohr–Coulomb model. The failure mode of tunnel face was shown related to water level. By considering the effect of seepage on failure mode, the wedge model was modified to calculate the limit support pressure under seepage condition. The water head around the tunnel face was fitted by an exponential function, and then an analytical solution to the limit support pressure under seepage condition was deduced. The variations in the limit support pressure on strength parameters of soil and water lever compare well with the numerical results. The modified wedge model was employed to analyze the tunnel face stability of Qianjiang cross-river shield tunnel. The influence of tide on the limit support pressure was obtained, and the calculated limit support pressure by the modified wedge model is consistent with the numerical result.

In this study, the shear strength parameters of the Kaolinite clay, as the control material, and the Kaolinite clay reinforced by different percentages of two different types of crumb rubber content have been evaluated. The consolidated drained and unconsolidated undrained triaxial and California bearing ratio tests have been conducted on the control and crumb rubber reinforced soils. Addition of crumb rubber would improve shear strength parameters such as cohesion, friction and dilation angles, stiffness and the ductility of the reinforced soil. 5, 10 and 15 % (by the weight of dry soil) of crumb rubber content were used in this study which were undergone confining stress levels of 100, 200 and 300 kPa and an optimum crumb rubber content is found, which results in the maximum bearing capacity of the soil. Also, due to the non-linearity of the failure mode of reinforced soil and inadequacy of Mohr–Columb envelope for describing the behaviour, a failure mode is proposed for the clay soils reinforced by crumb rubber. This failure criterion is useful for failure envelope of clay-rubber matrix.

Pile load tests and numerical analysis of a small-scale model pile in unsaturated clayey soil are presented in this paper. A small-scale model pile was simulated to bear a static axial loading in unsaturated soil using finite element method. All parameters used in the finite element method were obtained in laboratory tests, including the direct shear test, interface direct shear test, and filter paper method. The numerical analysis results were compared with the pile load test results. The results show that the general trend of pile load and pile head settlement relationship obtained by the numerical analysis shows a good consistence with the pile load test results. With increasing water content of the soil, the matric suction, dilatancy angle and shear strength decrease, and consequently the ultimate bearing capacity of pile decreases.

It is vital to control the settlement of ultra-high voltage and long span tower foundation because of the difficult construction and strict deformation control. Based on the thinking of deformation compatibility, the mechanical model of deformation compatibility between pile and soil is established. Relying on the long span tower project Lingzhou–Shaoxing ±800 kV DC transmission lines across the Yangtze River, through checking ultimate bearing capacity of existing pile foundation, it can be obtained that the present design foundation can effectively meet the upper 200–220 t load, but it cannot meet the load requirements about 300 t in the construction. The failures of tower foundation mainly display that piles cut into the soil with penetration type in the early condition. With the load increasing, the shallow soil and infrastructure gradually damage with the whole cap sinking, cushion layer destruction and the surrounding soil uplifting. As a result, tower foundation is unable to withstand the effect of upper overload and the whole tower becomes shear failure. The treatment scheme was proposed that it can improve the cushion thickness and strength combined with grouting consolidation to soil around the piles. Thus, the stability of tower foundation improves significantly and settlement was controlled within the permitted range of below 10 mm, which can meet the structure requirements. The results of numerical simulation based on deformation compatibility between pile and soil coincide well with field measured results.

This paper proposes a modified strain wedge (MSW) model for nonlinear analysis of laterally loaded single piles in clays. The MSW model is used to calculate the soil resistance under increasing pile deflection. The stress–strain behavior of clays in the MSW, which is needed to calculate the soil resistance, is described in terms of both hyperbolic and bilinear stress–strain relationships. The subgrade reaction modulus of soil below the MSW is assumed to equal the conventional subgrade reaction modulus and to remain constant under the lateral loading of the pile. The applicability of the proposed model was verified by eight case histories. The results indicate that (1) the predicted results are consistent with the measurements for all eight full-scale tested piles; (2) the bilinear stress–strain relationship is not recommended for clays because the clays usually have a large ε50 and, thus, they exhibit a linear behavior in the MSW during loading; (3) the predicted pile response is less sensitive to the effective friction angle than to the undrained shear strength; and (4) the proposed MSW model applies to normally consolidated clays and to overconsolidated clays until they reach their peak strength.

In this study, an assessment to excess pore water pressure generated around a single pile and pile group excited by two opposite rotary machines embedded in saturated sandy soil was considered experimentally. A small-scale physical model was manufactured to accomplish the experimental work in the laboratory. The physical model consists of: two small motors supplied with eccentric mass of 0.012 kg and eccentric distance (20 mm) representing the two opposite rotary machines, an aluminum shaft 20 mm in diameter as the pile, and a steel plate with dimensions of (160 × 160 × 20 mm) as a pile cap. The experimental work was achieved taking the following parameters into considerations: pile embedment depth ratio (L/d), spacing between piles (S) and operating frequency of the rotary machines. Twelve tests were conducted in medium dense fine sandy soil with 60 % relative density. In all these tests, the change in excess pore water pressure was measured around the pile at two spots: at the middle of the pile and at its tip. The results revealed that the generation of excess pore water pressure was affected by the following parameters: slenderness ratio of the pile, operating frequency of the machines, and the soil permeability. However, for all cases, it was found that the pore water pressure generated during operation was not greater than 20 % of the initial hydrostatic pressure. Using pile foundation reduced the amplitude of vertical vibration by about (300 %) for all operating frequencies, lengths of piles, pile spacings and number of piles. In addition, the presence of piles reduced the disturbance (fluctuation) in this amplitude by about (400 %). For single pile, and under the same operating frequency, a small decrease in the amplitude of vertical vibration resulted from increasing the length of the pile.

To reveal the deformation mechanism during tunneling in deep soft ground, triaxial unloading confining pressure tests and triaxial unloading creep tests were carried out on sandy mudstone specimens to study the dilatancy and fracturing behavior of soft rock. In the triaxial unloading confining pressure tests, the stress path and different unloading rates were considered to reflect the unloading characteristics of the excavation methods. The unloading rate effects and the rock damage evolution law are studied. The following conclusions are obtained from the results. Firstly, when the unloading rate is smooth, the peak strengths and deviatoric stress–strain curves under the unloading condition are close to those under the conventional loading condition. Secondly, the post-peak brittle characteristics are more apparent with the increasing unloading rates. Thirdly, the soft rock undergoes five deformation and failure regimes of elasticity, pre-peak unloading damage–dilatancy, post-peak brittle drop, linear strain softening and residual perfect plasticity under quasi-static smooth unloading of mechanized excavation which is mainly focused on in this study. Fourthly, the damage evolution law at the pre-peak damage–dilatancy stage follows an exponential function. Fifthly, during the post-peak stages, multistage microfractures are initiated, propagated and finally coalesced forming a shear-fragmentation band with a certain thickness, accompanied by significant volumetric dilatancy. In the triaxial unloading creep tests, multistep unloading of the confining pressure was applied, while the axial pressure was kept constant. The results show that when the deviatoric stress is larger and the experienced creep time is longer, the unloading effect and creep characteristics become more apparent accompanied with obvious lateral dilatancy, eventually leading to significant creep–dilatancy. The progressive failure with time is caused by the damage accumulating with time-dependent crack expansion, which can be called as ‘time-dependent damage and fracturing’. The reasons for the above evolution process are presented, then the deformation mechanism of soft rock is revealed. The soft rock deformation mainly consists of two parts. One part is the pre-peak damage–dilatancy and post-peak fracture–bulking produced at the excavation unloading instant. The other part is creep–dilatancy caused by time-dependent damage and fracturing in a period of time after excavation. The above-mentioned results of damage, dilatancy and fractures evolution process are in good agreement with the in situ monitoring results and previous studies about the surrounding rock convergence, fracturing and EDZ (excavation damaged zone) development.

The present study demonstrates the influence of operating speed on capacity of a midblock section of urban road. Speed – flow data collected at 12 midblock sections of 6-lane and 4-lane divided urban arterials in four metropolitan cities of India are analyzed to determine their capacity. Lane capacity was found to vary from 1482 pcu/hr to 2105 pcu/hr. This variation is explained on the basis of city size and driving behavior, which would influence the free flow speed on the road. Free flow speed was also measured at each section and these speed data were used to determine operating speed (85th percentile of free flow speed of standard car) on the road. Lane capacity was found to be strongly related with operating speed on a road and a second degree polynomial model is developed between the lane capacity and operating speed. This model is further validated by collecting speed flow data at two new sections and their capacity was estimated from field data and from the model developed in the study. The predicted capacity was found to be matching with field capacity and the maximum error was 0.10 percent. Operating speed on a road can vary due to road surface condition, side friction or similar other factors. All these will have influence on capacity of the road. The capacity model suggested in the present study can be a useful tool to determine capacity of an urban road from its operating speed data.

The present paper addresses the comparative study of two adjacent single-degree-of freedom structures for elastic and inelastic systems with and without pounding and also in the presence and absence of TMD under seismic excitations. The tuned mass damper considered for the present study is a passive device attached to single main structural unit in the form of weak storey at the top of main system. Total eight models have been considered depending upon the presence and absence of pounding as well as TMD in the analysis. The entire numerical simulation is carried out in time domain by considering the inputs of four real earthquake ground motions. An elastic adjacent structural system always overrates the pounding forces than the inelastic adjacent structural units. The use of TMD reduces the pounding forces in the adjacent structures. In pounding, structural displacement response is much sensitive for inelastic systems mostly under consideration or ignorance of TMD. Structural energy formation in the adjacent structures shows much variation with and without consideration of pounding as well as TMD.

The present study aims at the divination of the speed ranges of Level of Service (LOS) categories of urban traffic facilities. Free flow speed (FFS), congested travel speed, geometric and surrounding environmental conditions are considered to define LOS criteria for urban street in Indian context. Cluster analysis is found to be a powerful tool to delineate LOS criteria. Hard Competitive Learning (hardcl) method is used to classify large number of speed data obtained using Global Positioning System (GPS). Six cluster validation parameters are used to classify the urban streets as well as the LOS categories. It can be confirmed from the above research work that the LOS categories for different urban street class are lower than that of the values proposed by HCM 2000 and the average travel speed of LOS categories expressed in percentage of the free flow speed are lower than the values mentioned in HCM 2010.