---

We report engineering experiences from the critical task of relief well installation under high artesian flow conditions at the downstream toe of the Karkheh earth dam, Iran. Due to the establishment of excessive uplift pressure at the downstream toe of the Karkheh dam, installation of a series of new relief wells was considered to permanently relieve part of these pressures. The mentioned uplift pressure, as high as around 30 m above the ground level, was produced in a confined conglomerate aquifer bounded above and below by relatively impervious mudstone layers which reduced the safety factor of the dam toe to below 1.0. Investigations on the shortcomings of the old relief wells installed at the dam site showed that the main problems were: insufficient well numbers, insufficient well diameters, irregular well screens causing their blockage by time passing, and insufficient total opening area. Despite engineering difficulties and associated risk of downstream toe instability, installation of new relief wells was successfully completed under high artesian flow conditions” was successfully completed. The employed technique for the construction of the new relief wells under flowing artesian conditions was based on: 1) cement grouting and casing of the well, 2) telescopic drilling, 3) application of appropriate drilling fluid, and 4) controlling the artesian flow by adding a long vertical pipe to the top of the relief wells. Numerical modeling of seepage for the Karkheh dam foundation showed that, as a result of the installation of the new relief wells, the safety factor of the downstream toe increased to the safe value of 1.3 for the normal reservoir water level.

---

To investigate the saturation induced collapse deformation behavior of rockfill material, a set of large-scale triaxial tests were conducted in saturated and dry-saturated conditions. Specimens were tested under various confining pressures. For dry-saturated tests, specimens were sheared in various stress levels. Results of all dry saturated tests indicate a sudden reduction in the specimen volume during the submerging process. The ratio of the minimum axial strength of a submerged specimen (at the end of the saturation process) to the shear strength of the specimen before saturation is defined as the coefficient of stress recovery, Csr. Results show that this ratio increases as the confining pressure increases, and decreases as the shear stress level increases. According to the results of dry-saturated tests, reduction values of the internal friction angle caused by saturation (c), the ratio of the elasticity modulus of the material after saturation to its elasticity modulus in dry condition, i.e., Ewet/Edry, and the saturation induced sudden volumetric strain (vc) decrease as the confining pressures increase. However the shear stress level does not have any meaningful effect on the variation of c, Ewet/Edry and (vc).

---

Stabilization of earth slopes with various proposed methods is one of the important concerns of geotechnical engineering. In this practice, despite numerous developments, design conservativeness and high costs of stabilization are the issues yet to be addressed. This paper not only deals with pile location optimization but also studies the effects of the pile length by using line segments slip surface (non-circular). Taking into account the line segments slip surface in stabilization of earth slopes is a new topic which has been addressed in this paper. The line segments slip surface is actual slip surface and for determining the pile location it can lead to the actual length of the pile. The line segments critical slip surface is obtained by using the Alternating Variable Local Gradient (AVLG) optimization method. AVLG is an approach in optimization process and it is based on the Univariate method. The line segments form the initial and critical slip surface. Pile improper installation and inadequate length not only fails to increase the factor of safety, but also reduces it. The analyses are performed using the limit equilibrium (LE) method. Results of these analyses are acceptable and are properly consistent with the results obtained by other researchers.

---

Workers who carry out manual rebar tying tasks are exposed to muscular-skeletal injuries associated with the use of manual tools and the movements associated with them (force, repetitiveness and awkward wrist postures). This paper presents a background on musculoskeletal injuries directly linked to manual and mechanical rebar tying method is conducted. The objective of this study is to compare the traditional manual rebar tying method to the innovative mechanical technique. The methodology carried out follows a qualitative and a quantitative analysis of both processes. Firstly, a qualitative analysis is performed by semi-structured interviews to workers. Secondly, a quantitative study is carried out in the region of Andalusia (Spain). This field study includes on-site measurements of lengths of time activities. According to the methodology developed by the International Labour Organization, the work timing is calculated and a comparison is given. Results state that the operators adapt without difficulty to the mechanical method and it could result in better performance, whilst reducing some of the risks deriving from the manual tying technique.

---

To increase the safety of structures against strong ground motions and their life due to environmental issues on the earth and saving in terms of materials, it is necessary to expand and upgrade seismic resistant systems. However, more cost-effective systems which have sufficient influence on the seismic performance of structures and also more compatibility with the regional conditions, will be more desirable than other systems. One of the seismic resistance systems is seismic isolation. In the event of interest in using the seismic isolation system for a mounted building on piles, the costly construction of piles and isolation equipment shall be provided simultaneously. The seismic isolating using sleeved-piles which is generally used in combination with various damper systems, can help to overcome this issue. In this research a seismic isolator system using sleeved-pile has been studied while considering the damping behavior of the soil-rubber mixture as the only source of damping. To investigate the proposed system, a series of tests including static lateral load test, dynamic free and forced vibration tests, were performed on a model pile in a field laboratory which has been constructed for this purpose. According to results of tests the proposed system has a good deformation ability and damping characteristics, and as a method of seismic isolation is completely efficient.

---

The Dynamic Probe is an effective tool used in site investigation. It is more economic than the use of direct drilling, particularly in explorations with moderate depth. This paper presents an experimental study to investigate the capability of using dynamic probing to evaluate the shear strength and compaction percent of fine soil. A series of dynamic probe tests were carried out at 6 different sites in the Khozestan, Hormozgan and Qom provinces in the central and southern regions of Iran. The repeatability of the results is considered and new empirical equations relating the dynamic point resistance to undrained shear strength and compaction percent are proposed. For undrained shear strength evaluation of fine soils, i.e. clay and silty clay soils, a reliable site-specific correlation between qd and Cu can be developed when considering the correlation between log qd and log Cu. Also compaction present can be evaluated by qd. These equations can be developed to provide site-specific relationships based upon geotechnical data at each new location. Using this approach an estimation of the undrained shear strength Cu and compaction percent CP can be determined from dynamic probe tests with acceptable accuracy. The present paper also encourages the wider application of dynamic probing for site investigation in fine soils.

---

In this paper, evaluation of torsional stiffness in beam and slab bridge deck elements is presented. A beam and slab bridge decks structurally behave as a grillage. A grillage has an efficient transverse load distribution due to transverse asymmetric load. In the case of bridge deck without transverse beams in the span, transverse load distribution depends on the torsional stiffness of longitudinal beams, transverse beams over the supports and deck slab. The results of load testing conducted on series of bridges in Croatia are compared with results obtained on different numerical grillage models in which torsional stiffness of main structural elements was varied. Five different numerical models for each tested bridge are used. To evaluate torsional stiffness of main structural elements of the bridge the transverse distribution coefficients are introduced. The design value of the coefficients of torsional stiffness reduction for verification of the serviceability limit state (SLS), with assumption of normal probability distribution is determined. The same coefficient is calculated using recommendation for torsional stiffness reduction in concrete elements defined by Model code CEB-FIB 1990 (MC 90). According to conducted analyses the design value of the coefficient of torsional stiffness reduction for verification of the serviceability limit state of main structural elements of beam and slab bridge deck is proposed.

---

Energy conservation in buildings plays a vital role for sustainable development of societies and nations. Although, newer buildings in developing nations are being constructed using energy conservation approach, existing buildings have higher energy demand to meet the desired comfort. Excessive energy demand for cooling the built environment is a major problem over most of the arid climatic zones. The problem is predominant in all the top storied buildings which are directly under exposed roof condition. In order to reduce the overheating of the roof surface a composite combination of reflecting-cum-insulating (R-I) material was developed. The sustainable materials viz., expanded polystyrene (construction waste), saw dust (industrial waste), and the false ceiling panels prepared from industrial waste were used for the development of sustainable R-I material. The R-I material was retrofitted over the existing roof of a model room in an educational building over composite climate (Nagpur, India) and was analyzed experimentally for the period of a year. The thermal resistance of the overall roof assembly was increased from 0.28 to 0.55 m² K/W, which in turn helped to achieve 16% of the duration of the year under thermal comfort. The developed R-I material has also an advantage of low cost (INR 900 per sq. m.) of installation as well as light weight (50 kg/m²) retrofitting solution. The R-I product can further be applied on larger roof areas by the designers to reduce the cooling load of the built environment as well as increase the occupants comfort over the local climatic zone.

---

The current research intends to study the possibility of producing fiber recycled self-compacting concrete (FRSCC) using demolitions as a coarse aggregate (crushed red brick and crushed ceramic). Steel fibers were used in recycled self-compacting concrete (RSCC) to improve fresh and hardened properties of this type of concrete. Thirty nine concrete mixes were prepared to achieve the aim proposed in this paper. Steel fiber volume fraction varied from 0 to 2.0% by the volume of concrete with aspect ratio 65. The fresh properties of FRSCC were evaluated using slump flow, J-ring and V-funnel tests. Compressive strength, tensile strength, flexural strength and density tests were performed in order to investigate mechanical properties. The optimum volume fraction of steel fibers was 0.25% and 1.0% for the mixes contained crushed red brick and ceramic as a coarse aggregate respectively. At optimum content of steel fibers, the compressive strength for the RSCC mixes with steel fibers improved by 11.3% and 31.8% for the mixes with crushed ceramic and crushed red brick, respectively with respect to control mix. Also the tensile strength and the flexural strength for the mixes were improved

---

The current building codes provide limited prescriptive guidance on design for protection of buildings due to progressive collapse. Progressive collapse is a situation in which a localized failure in a structure, caused by an abnormal load, such as explosions or other happenings. Three procedures, often employed for determination of the structural response during progressive collapse i.e. linear static procedure (LSP), nonlinear static (NSP) and nonlinear dynamic (NDP) analyses. In nonlinear static analysis, a force-based method is applied and the structure is pushed down to the target force. In this research, a new displacement-based method will be proposed for nonlinear static analysis. In displacement-based method, the structure is pushed down to target displacement instead of target force (similar to the one in seismic pushover analysis). To make a nonlinear static analysis, instead of increasing the load around the area of the removed column, a maximum displacement is calculated and the upper node of the removed column is pushed up to target displacement. Here, to determine the target displacement, results from nonlinear dynamic and linear static analyses are compared. This paper tries to present a formula to calculate the target displacement using the linear static rather than the nonlinear dynamic analysis. For this reason, 3 buildings with 3, 5 and 10 stories have been seismically designed and studied. The results show that, this method is much more accurate in comparison to the recommended approach in current codes. Also, this method does not have the limitations of force-based nonlinear static analysis.

---

Construction industry projects impose unsought constraints on employers to manage and define new projects including investment risk, performance variation and diversity of the project. Annually, a significant part of the governmental budget is being spent to execute water and wastewater projects in Iran. However, further projects are on demand to develop the country. The aim of this study is to develop courses of action to attract private partnership into the projects defined and executed in the water sector of the Iranian Ministry of Energy. To determine the criteria and implementing the proposed strategies, SWOT (Strength, Weakness, Opportunity, Threat) method was used as a powerful tool for understanding the context of the organization. To understand the importance of criteria, we weighted them then the extracted strategies from SWOT matrix (ANP method) was prioritized and divided into short- and long-term range in terms of performance and capabilities. According to the results, SO strategies have more weight than other strategies. Therefore, regarding the nature of strategies, the opportunities should be completely used through reinforcing the strengths and short- and long- term periods planning.

---

Soil contamination by heavy metals is a worldwide environmental challenging issue. Due to the industrial activities, a site located in North West of Shiraz (Fars Province, Iran) has the potential to be contaminated by different heavy metals. The objective of this study was to assess the effectiveness of dicalcium phosphate (DCP) and sodium tripoly phosphate (STPP) for immobilizing lead, copper and cadmium in contaminated soils. Leaching column tests performed on the soil without any stabilizing agent demonstrated a uniform leachate of metals in the effluent during the experimental period. After mixing DCP or STTP with the contaminated soils, the release of all three heavy metals through the effluent was ceased. The results further indicated that 0.1 to 0.2 percent by weight of these stabilizers is effective for immobilizing of applied metals through the experimental soil. Penetration of acid sulfuric solution with pH of 5 had no influence on stabilizing efficiency and almost whole the applied heavy metals seem to be immobilized through the soil media.

---

ABSTRACT The influence of the sand placement method above geotextile layer on interface shear strength behavior was investigated. Seven different types of woven and non woven geotextile were used with only poorly graded sand. The investigation involved placement of sand layer through inclined horizontal plane with different angles. This step constitutes a fundamental step for assessing soil to be deposited in different plane and therefore with different internal soil fabric. The interface shear strength was evaluated by using direct shear test. Although the investigated soil is uniform poorly graded sand, the influence of the deposit plane was significant especially for nonwoven geotextile. Differences in soil interface shear strength associated with the tested geotextiles samples shows that samples with higher mass per unit area and same opening sizes had the higher interface friction angle regardless the bedding plane. Influence of bedding plane on interface modulus of elasticity which used in most of interface modeling was investigated using Janbu’s formula. It is noted that the use of secant interface modulus of elasticity at 1% strain and at 50% of peak stresses gave a consistent prediction of n and Ku constant appear in Janbu’s formula for all types of geotextile. The above results were reflected in the prediction for interface molded such as Chen and Juran as shown. Therefore, the existing interface modeled is needed to be modified to account for the method that the sand is being placed above the geotextile layer.

---

A study has been conducted on the bearing capacity of strip footings over sandy layered soils using the stress characteristic lines method. Traditional bearing capacity theories for specifying the ultimate bearing capacity of shallow foundations are based on the idea that the bearing layer is homogenous and infinite. However layered soils are mainly happening in practice. The stress characteristic lines method is a powerful numerical tool in order to solve stability problems in geotechnical engineering. In the present paper, an appropriate algorithm is derived for estimating the static bearing capacity of strip footing located on two layered soils using the stress characteristic lines method. Some numerical and experimental examples are presented in order to validate the proposed algorithm. Some graphs and equation are presented for initial estimating the effective depth of strip footings located on two layered soils.

---

Risk allocation is the definition and division of responsibility associated with a possible future loss or gain arising from an identified risk. Quantitative approaches to risk allocation have been developed to overcome the limitations of qualitative approaches, especially the issue of the amount of risk to be borne by each party. This paper presents a cooperative-bargaining game model for quantitative risk allocation that extends the previous existing system dynamics SD-based model. The behavior of contracting parties in the quantitative risk allocation process is modeled as the players’ behavior in a game. The proposed model accounts for both the client costs and the contractor costs to perform the quantitative risk allocation process. To evaluate the performance of the proposed model, it has been employed in a pipeline project. Quantitative risk allocation is performed for the inflation as one of the most important identified risks. It is shown that using the proposed cooperative-bargaining game model, both the client and contractor costs are decreased in comparison to the previous SD-based risk allocation approach.

---

This paper presents a novel approach to solve the double-track railway rescheduling problem, when an incident occurs into one of the block sections of the railway. The approach restricts the effects of an incident to a specific time, based on which the trains are divided into rescheduled and unchanged ones, so that the latter retain their original time-table after the incident. The main contribution of this approach is the simultaneous consideration of three rescheduling policies: cancelling, delaying and re-ordering. A mixed-integer optimization model is developed to find optimal conflict-free time-table compatible with the proposed approach. The objective function minimizes two cost parts: the cost of deviation from the primary time-table and the cost of train cancellation. The model is solved by CPLEX 11 software which automatically generates the optimal solution of a problem. Also, a meta-heuristic solution method based on simulated annealing algorithm is proposed for tackling the large-scale problems. The results of an experimental analysis on two double-track railways of the Iranian network show an appropriate capability of the model and solution method for handling the simultaneous train rescheduling. The results indicate that the proposed solution method can provide good solutions in much shorter time, compared with the time taken to solve the mathematical model by CPLEX software.

---

Investigating the seismic amplification of incident waves induced by subsurface cavities and characterizing its patterns for the ground surface are important in seismology, geophysics and earthquake engineering both in theory and practical application. Nowadays, it has been established that the seismic ground response above subsurface structures can be different from the free-field motion during earthquakes. In this regard, this research studied preliminary results of a numerical parametric study on the seismic response of the ground surface above subsurface cavity. Basically, this study is applied to get new idea to move a step forward in site response analysis which can be used in the seismic microzonation of areas located above underground spaces. For analysis purposes, a numerical time-domain analysis is performed by utilizing a robust numerical algorithm working based on the boundary element method. It is observed that the amplification of the ground surface underlain by a shallow elliptical cavity is increased in long periods. Some preliminary simple relationships and tables are presented which could be used while introducing simple preliminary ideas for modification of the standard design spectra in building codes and seismic microzonation studies.

---

Abstract To meet construction demands, reinforcement and stabilization methods have been widely used to improve properties and mechanical behavior of clays. Although cement stabilization increases soil strength, at the same time reduces ductility which is of paramount importance in roads, landfill covers, etc. In current study, kaolinite was stabilized with 1, 3 and 5% cement and mixed with 0.05, 0.15, 0.25 and 0.35% polypropylene fibers to increase ductility. Samples were cured at 35°C for 1, 7 and 28 days and subjected to unconfined compression tests. Results showed that inclusion of discrete fibers to uncemented and cemented kaolinite reduced stiffness and the loss of post-peak strength and changed brittle behavior of cemented samples to a more ductile behavior. Cement and fiber contents as well as curing period were found to be the most influential factors and fiber – soil interaction was influenced by binding materials.

---

The purpose of this paper is to improve the intelligence and universality of classical method for gating control in the SCOOT system. Firstly, we introduce a method to identify spillovers, and use the occupancy threshold for spillover recognition to trigger this special control logic. Then we present an influence rate model for links upstream of the bottleneck link, and a share ratio model for the downstream links, after analyzing the interrelationship of the traffic flows among adjacent traffic links. With known threshold values for the influence rate and share ratio, we propose a rule and process for selecting the intersections that should be included in the sub-area of the gating control. Thirdly, we determine total capacity adjustments for the incoming and outgoing streams of bottleneck links, with the aim of dissipating the queue to a permissible length within a given period of time. After that, the apportion models for the total adjustments among different paths and links are presented, along with the correlation coefficients of the traffic flows between the bottleneck link and the other links. Next, we ascertain the capacity decrements and increments for the gated and benefiting streams, and define the optimization schemes so as to calculate splits for the gated and benefiting intersections. Finally, we evaluate the advanced method using a VISSIM simulation. The results show that new control method brings significant and positive effects to the bottleneck link itself and to the entire control area.

---

This study focused on the design of heat-resistant asphalt mixture for permafrost regions. Vermiculite powder with low thermal conductivity was used to replace some of the fine aggregates in asphalt mixture to lower the thermal conductivity of asphalt mixture. Asphalt mixtures with different mass ratios (0, 3, 6, 9 and 12%) of vermiculite powder were prepared for performance and thermal property evaluation. Wheel tracking test, low-temperature bending beam test, freeze-thaw splitting test and fatigue test were conducted to evaluate the influences of vermiculite powder on the high-temperature rutting resistance, low-temperature cracking resistance, moisture stability and anti-fatigue performance of asphalt mixture. Mathis TCI analyzer was used to analyze the influences of vermiculite powder on the thermal conductivity of asphalt mixture. Temperature monitor system was used to figure out the influences of vermiculite powder on the inside temperature of asphalt mixture. It is proved that vermiculite powder has no significant influences on the performances of asphalt mixture while it obviously affects the thermal property of asphalt mixture. By addition of 9% to 12% vermiculite powder in asphalt mixture, the performances of asphalt mixture can still well meet the performance requirements for permafrost regions the thermal conductivity can be reduced by 40% to 55% and the inside temperature of asphalt mixture can be lowered by 1 to 2°C. It proves the feasibility by using vermiculite powder to produce heat-resistant asphalt mixture for permafrost regions.