Seismic behavior of triple tunnel complex in soft soil subjected to transverse shaking

Combining multiple tunnels into a single tunnel complex while keeping the surrounding area compact is a complicated procedure. The condition becomes more complex when soft soil is present and the area is prone to seismic activity. Seismic vibrations produce sudden ground shaking, which causes a sharp decrease in the shear strength and bearing capacity of the soil. This results in larger ground displacements and deformation of structures located at the surface and within the soil mass. The deformations are more pronounced at shallower depths and near the ground surface. Tunnels located in that area are also affected and can undergo excessive distortions and uplift. The condition becomes worse if the tunnel area is larger, and, thus, the respective tunnel complex needs to be properly evaluated. In this research, a novel triple tunnel complex formed by combining three closely spaced tunnels is numerically analyzed using Plaxis 2D software under variable dynamic loadings. The effect of variations in lining thickness, the inner supporting structure, embedment depth on the produced ground displacements, tunnel deformations, resisting bending moments, and the developed thrusts are studied in detail. The triple tunnel complex is also compared with the rectangular and equivalent horizontal twin tunnel complexes in terms of generated thrusts and resisted seismic-induced bending moments. From the results, it is concluded that increased thickness of the lining, inner structure, and greater embedment depth results in decreased ground displacements, tunnel deformations, and increased resistance to seismic-induced bending moments. The comparison of shapes revealed that the triple tunnel complex has better resistance against moments with the least amount of thrust and surface heave produced

Political, Economic, Social and Legal Women Empowerment

This article studies the predicament of women’s rights in Pakistan. Analysing the policies related to women rights given by the successive governments in the ruling era of General Pervaiz Musharraf, this study finds that despite the scarce resources, Pakistan and the policies for women empowerment and development had potential to produce good results but they failed to deliver due to lack of political will of the previous governments to implement those policies and to establish the goal of universal education especially for women. The Zia Regime had effected and harmed women’s rights; therefore he had neglected the 51% population i.e. women of the country which portrayed the very negative image of the country to the world. The democratic governments of post-Zia period worked positively in this direction since they required women vote which constituted half of the franchise. The government of General Pervaiz Musharraf promoted women development and empowerment sector f and showed strong will towards promoting women’s right. This study concludes that goal of women’s rights could only be achieved with forceful political will of the government. Social issue that earned the Musharraf regime a great deal of prominence is the Empowerment of Women. Women empowerment received the much deserved spotlight during Musharraf's era as this agenda was considered one of the major building blocks for economically stable and progressive Pakistan. General Pervaiz Musharraf was very much concerned towards the better and soft image of Pakistan in the world. He introduced laws and repealed the discriminatory laws towards women. Pervaiz Musharraf tried his level best to brand the positive image of the country in the world with new laws and reforms being introduced, this was considered as a golden era in context of legislation made for women empowerment in Pakistan. The steps taken can be broadly categorized into two sets i.e. Political and Economic Women Empowerment and Legal and Social Women Empowerment. Keywords: Women Empowerment, Social, Political, Economic

Comparison of Different Combined Multiple Tunnel Complexes in Soft Soil under Seismic Vibrations

The resilience of underground tunnels has gained paramount importance recently, driven by the need to ensure the safety and functionality of critical transportation and infrastructure systems during seismic events. Underground tunnels are prone to severe damage when the soil condition is poor and located in a high seismic zone. While the behavior of individual tunnels has been extensively studied, the concept of multiple tunnels combined into a large tunnel complex is relatively new, with limited available research focusing on rectangular-shaped tunnel complexes and requiring a more detailed examination. This study parametrically analyzes two novel and unconventional structures in soft soil, i.e., twin and triple tunnel complexes resulting from the combination of closely spaced circular twin and triple individual tunnels. Seismic records from Coyote (US, 1979), Kobe (Japan, 1995), and Kocaeli (Turkey, 1999) have been used to determine the produced surface displacements, tunnel distortions, lateral stresses on the tunnel structures, and the induced seismic forces, including thrusts, shear forces, and bending moments. The results are then compared with the conventional rectangular-shaped tunnel complex, which is also analyzed under the same conditions. The comparison shows that the twin and triple tunnel complexes are comparatively better seismic performers than the conventional rectangular tunnel complex, with reduced ground displacements produced, lesser incurred structural distortions, experienced lateral stresses, and induced seismic forces. Doi: 10.28991/CEJ-2023-09-12-01 Full Text: PD

Experimental Investigation of Isobaric specific heat capacity (Cp) of 9-ethylcarbazole in liquid and solid state

Liquid organic hydrides, e.g. 9-ethylcarbazole, are potentially interesting hydrogen storage materials becauseof their reversible hydrogen sorption properties. In this study, the isobaric specific heat capacity of 9-ethylcarbazole in solid and liquid phases was investigated using adiabatic calorimeter. The experimentalsetup consisting of two basic components adiabatic calorimeter and pressure unit was developed. To calibratethe apparatus the specific heat of the water was measured. The experimental data points were obtained at 0.1MPa to 0.88 MPa pressure range and 353 K to 480 K temperature range. The specific heat dependence onpressure and temperature was presented. The increase in specific heat of 9-ethylcarbazole was observed withincreasing pressure and temperature for solid phase, while for liquid phase decrease in trend was observed forincreasing pressure.Keywords: 9-ethylcarbazole, Adiabatic Calorimeter, Specific Heat, Nitrogen Gas Cylinde

A numerical evaluation of structural hot-spot stress methods in rib-to-deck joint of orthotropic steel deck

This study numerically investigates the limitations of structural hot-spot stress (SHSS) methods and proposes a guideline for the calculation of hot-spot stresses, which can be used for the better evaluation of fatigue-related problems. Four different SHSS evaluation methods have been applied to the rib-to-deck (RD) welded joint in orthotropic steel deck (OSD). These methods are used to calculate SHSS at this critical joint utilizing finite element analyses (FEA) based software Siemens NX.12. The limitations and the accuracy of these methods have been observed under different element types and meshing techniques. Moreover, the effect of the nodal-averaging feature is being studied. Two types of governing stresses are produced by the application of Eurocode fatigue load model-4. Essentially, the bending in deck-plate produces highly non-linear stress at the deck-toe, and the membrane effect in rib-plate generates linear stress at the rib-toe. Guidelines are proposed considering different parameters on these two stress states by applying SHSS evaluation methods. In comparison to other SHSS approaches, the International Institute of Welding (IIW) quadratic stress extrapolation (QSE) method shows better results for solid single-element, and the American Society of Mechanical Engineers (ASME) through thickness stress linearization (TTSL) method stands out in solid cubic-mesh technique. In general, shell elements have more consistent SHSS results as compared to solid elements for both stress states

Numerical evaluation of early-age crack induction in continuously reinforced concrete pavement with different saw-cut dimensions subjected to external varying temperature field

Since 1970, continuously reinforced concrete pavements have been used in Belgium. The standard design concept for CRCP has been modified through several changes made in the design parameters to eliminate the cluster of closely spaced crack patterns, since these crack patterns lead to the development of spalling and punch-out distresses in CRCPs. Despite adjusting the longitudinal reinforcement ratio, slab thickness, and addition of asphalt interlayer, the narrowly spaced cracks could not be effectively removed. The application of transverse partial surface saw-cuts significantly reduced the probability of randomly occurring cracks in the reconstruction project of the Motorway E313 in Herentals, Belgium. The field investigation has also indicated that the early-age crack induction in CRCP is quite susceptible to the saw-cut depth. Therefore, the present study aims to evaluate the effect of different depths and lengths of the partial surface saw-cut on the effectiveness of crack induction in CRCP under external varying temperature field. For this purpose, the FE software program DIANA 10.3 is used to develop the three dimensional finite element model of the active crack control CRCP segment. The characteristics of early-age crack induction in terms of crack initiation and crack propagation obtained from the FE model are compared and discussed concerning the field observations of the crack development on the active crack control E313 test sections. Findings indicate that the deeper saw-cut with longer cut-lengths could be a more effective attempt to induce the cracks in CRCP in desirable distributions to decrease the risk of spalling and punch-out distresses in the long-term performance of CRCP. These findings could be used as guidance to select the appropriate depth and length of saw-cut for active crack control sections of CRCP in Belgium

Evaluating the early-age crack induction in advanced reinforced concrete pavement using partial surface saw-cuts

The technological innovation of continuously reinforced concrete pavement (CRCP) that contains a significantly reduced amount of reinforcement and the same fundamental behavior as CRCP is called advanced reinforced concrete pavement (ARCP). This new concept of a rigid pavement structure is developed to eliminate unnecessary continuous longitudinal steel bars of CRCP by using partial length steel bars at predetermined crack locations. In Belgium, partial surface saw-cuts are used as the most effective crack induction method to eliminate the randomness in early-age crack patterns by inducing cracks at the predetermined locations of CRCP. The reinforcement layout of ARCP is designed based on the distribution of steel stress in continuous longitudinal steel bar in CRCP and the effectiveness of partial surface saw-cuts as a crack induction method. The 3D finite element (FE) model is developed to evaluate the behavior of ARCP with partial surface saw-cuts. The early-age crack characteristics in terms of crack initiation and crack propagation obtained from the FE simulation are validated with the field observations of cracking characteristics of the CRCP sections in Belgium. The finding indicates that there is fundamentally no difference in the steel stress distribution in the partial length steel bar of ARCP and continuous steel bar of CRCP. Moreover, ARCP exhibits the same cracking characteristics as CRCP even with a significantly reduced amount of continuous reinforcement

Combining bored tunnels : optimal construction order of multiple independant shield-driven tunnels

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Standardization and optimization of orthotropic steel deck with numerical modelling

In this paper, standardization and optimization of Orthotropic Steel Deck (OSD) is carried out to increase its usage as an essential bridge component. OSD’s are more often used in the long span bridges because they considered expensive and more complex structure. There are fatigue crack complications associated with these type of steel decks due to their direct contact with the heavy cyclic loading. The idea of standardizing the OSD’s is floating in the research industry for last two decades. To facilitate this concept numerical simulation study is carried out with and without additional cutouts with different deck thicknesses and span lengths. The Cross beams without stress relieving cutouts have been introduced which will reduce the labor cost for special cutouts preparation and increase the fatigue endurance of critical welded joints. Based on these numerical results; recommendations have been made. Standardization and optimization of OSD’s will definitely increase their usage in bridges

School teachers and principals’ experiences during COVID-19 in Pakistan

As a result of the COVID-19 pandemic, educational activities were disrupted globally. In Pakistan, schools were also closed, and though some schools had started teaching online, the staff (including principals and teachers) and students\u27 readiness for education during the pandemic remained unexplored. An internet-based survey was conducted to explore the experiences of the teachers and principals during the lockdown. The survey included both open-ended and closed-ended questions. Responses were collected from respondents in different parts of Pakistan, with the majority coming from Sindh and coming from both the private and public sector. While the respondents from private schools reported that they could teach online, the respondents from government schools could not continue the teaching process during the lockdown phase. School principals focused on acquiring technology for online teaching and offering skills development sessions. They used a variety of methods to monitor teaching and learning. Teachers relied on a mix of synchronous and asynchronous teaching. Infrastructure issues posed numerous challenges. Findings highlight an urgent need for teacher education programmes to incorporate digital literacy development and enhance pedagogical understanding of engaging students in online teaching environments and exploring solutions such as blended learning. The findings also draw our attention to questions of equitable access to quality education for all in Pakistan