Construction Stage Analysis Research Articles

Analysis and Design of Cable Stayed Bridge

Cable Stayed Bridges are one of the most fascinating icons in the field of Engineering and are commonly used bridge typologies for spans between 200m and 1100mm due to their structural efficiency, cost and aesthetics. The basic structural form of a cable-stayed bridge is a series of overlapping triangles comprising the pylon, the cables, and the girder. All these members are under predominantly axial forces, with the cables under tension and both the pylon and the girder under compression. Axially loaded members are generally more efficient than flexural members. This contributes to the economy of the bridge. In this project, we have made an attempt to analyses a 200m span Cable Stayed Bridge using the STAAD Pro software based on the design parameters which includes the bending moment, shear force and displacement, Reaction Graph, Total Quantity Materail, etc. Key Words: Cable Stayed Bridges, Unknown Load Factor Optimization, Construction Stage Analysis, Influence Line Diagram (ILD), SFD BMD Diagram, Analysis Design.

Analisis Stabilitas Tempat Pembuangan Akhir (TPA) Sampah Akibat Pengaruh Perubahan Sifat Mekanis Material Sampah

The stability of landfill is a crucial aspect of waste management. Numerous factors influence the stability of landfill, one of which is the alteration of the mechanical properties of the waste material. This research aims to analyze landfill stability by considering the effects of changes in the mechanical properties of waste material. A construction stage analysis was conducted to model the process of altering the mechanical properties of waste material. The analysis was divided into 13 stages corresponding to the number of landfill steps. The initial five stages were modeled as waste with an age of < 5 years, stages 6-10 were modeled as waste with an age of 5-10 years, and the last three stages were modeled as waste with an age of > 10 years. Stability analysis using the finite element method was conducted using the concept of shear strength reduction. The analysis results indicated changes in the landfill's safety factor throughout its operational period. Stages 1-5 experienced changes in the safety factor, although these changes were not significant. Stages 6-10 witnessed a considerable decrease in the safety factor before experiencing an increase in stage 11, followed by a continuous decline until the end of stage 13. Despite changes in the safety factor during the operational process, the overall safety factor values obtained still met the minimum safety factor criteria required.

A modeling strategy for the simulation of box sections with layered shell elements

This paper presents a numerical strategy to model box sections from bridge girders using horizontal layered shell finite elements. The basic idea is to avoid the construction of more computational expensive meshes based on the use of folded shell and brick finite elements. The numerical strategy imposes the deactivation of those layers related to empty spaces within the bridge cross-section. The performance of this technique is explored by means of two demanding practical applications related to bridge structures with constant and variable deck thicknesses. The first application deals with the static truck load test of the Caynarachi Bridge, located in Peru, and for which measured field data exists, while the second application is related to the construction stage analysis of a box bridge structure including time effects due to concrete creep, shrinkage and steel relaxation. The results demonstrate that the studied technique acceptably correlates with the measured field data,expressed in terms of vertical displacements,with correlation coefficients exceeding 0.94.Additionally, the outcomes align well with the results of other numerical techniques, allowing applicants to use this simplified modeling approach in daily design office.

Bridge Capacity Assessment through LRFR Method and Bridge Seismic Performance Evaluation Using the PBSD Concept: Case Study

In this study, a comprehensive evaluation was conducted of the condition and performance of a concrete arch-type bridge located in close proximity to a fault. Utilizing the LRFR capacity assessment method and seismic performance analysis through the NLTHA process based on the PBSD concept, finite element modeling (FEM) was employed with a focus on construction stage analysis and model updating for calibration to site conditions. The assessment encompassed the determination of the rating factor for structural elements under service and ultimate limit state loading. Performance analysis under seismic loads includes an examination of engineering demand parameters such as concrete and reinforcement strains in columns, subjected to varying seismic hazard levels. Additional scrutiny involves assessing bearing displacement and overturning potential to identify potential damage before column failure. The primary objective of this research was to investigate pertinent and efficient techniques for evaluating bridge capacity and seismic performance. A thorough understanding of these methods is expected to facilitate the identification of suitable solutions to enhance the safety and reliability of bridges in Indonesia.

Construction phases assessment for a railway tunnel

Major geotechnical issues related with tunnel construction phases are addressed. Focusing on an excavation scenario with reinforced concrete retaining walls in prevailing clayey soils, locally including sandy and silty-sandy layers, this study explores both drained and undrained conditions and considers various boundary conditions. Using the Finite Element (FE) method, a construction stage analysis of a tunnel located in the alluvial deposits of the Po Plain (northern Italy) in an urban area is carried out. This tunnel will serve the burying works of the Ferrara-Codigoro railway line, which are still underway. Based on hydrogeological conditions, the developed models take alternatively account of: (1) drained conditions with horizontal water table; (2) drained conditions with sloping water table (due to differences in water table depth between tunnel location and surrounding territories), and (3) undrained conditions with horizontal water table. Further complexity is introduced by incorporating buildings with either rigid or deformable foundations into the FE model. The fundamental role played by the boundary conditions is emphasized. Therefore, a detailed understanding of the exact sequence of construction phases and a good knowledge of the subsoil hydrogeological conditions result to be of utmost importance to capture induced settlements.

On the construction stage analysis of historical masonry vaults

On the construction stage analysis of historical masonry vaults

Mapping environmental problems in the new capital city of “Nusantara” as a foundation for sustainable development governance

Indonesia moved the country’s capital from Jakarta to Kalimantan Island. This activity is a major breakthrough, but if done incorrectly it can be a serious challenge, especially from an environmental perspective. This research aims to identify environmental problems in the development of Indonesian capital cities. This information was obtained through literature studies and field observations. City management studies, especially the development of the nation’s capital, need to be directed so as not to cause environmental damage problems. The mapping process starts from the pre-construction stage, construction stage, operational stage or environmental impact analysis. The mapping results show that environmental problems need to be mapped in the form of types of activities with a social, economic and environmental approach in accordance with sustainable development standards starting from a social approach to ensure the fulfillment of citizens’ rights in improving the quality of the environment city. The results of impact identification conclude that there is a positive impact on improving community welfare and there is a negative impact that increases the burden on the environment. An economic approach by ensuring the fulfillment of citizens’ rights in obtaining decent work and an environmental approach by paying attention to air, water quality and waste management in accordance with technological standards and following applicable laws and regulations. As for alternative conclusions for resolving environmental problems, community model governance is governance with a community approach for activities that have an area of less than 5 hectares and the complexity of environmental impacts is less than three impacts, while the complexity of environmental impacts is more than three impacts. of the three impacts are managed using a collaborative model.

Correction Factor Method As A Substitute For Sequential Construction Analysis Of Buildings

Abstract: Within the sphere of structural analysis, a method of paramount importance emerges - the Correction Factor Method. Unlike conventional approaches, this method stands as a stalwart against the complexities of non-linear structural behavior. It pioneers a path that diverges from the linear norm, offering precision and insight where others falter. The structural parts of the building are analyzed in one step using linear static analysis method by assuming that the structure will be subjected to full load after the finishing of the construction completely. In reality things work in other way the dead load from each structural members and finishing materials are imposed in different stages as the structure is constructed storey by storey. Similarly the stability of frame changes at every stage of construction. Because of this changes the loads assumed in conventional analysis vary in the construction process and the results obtained in the traditional analysis will be unstable. Thus the structural frame should be analyzed in every structural construction stage by keeping variation of loads. This process is called as Construction Stage Analysis this process considers all the uncertainties precisely. This process is a time consuming process as the analysis is a complex process. Thus Correction factor method can be introduced where the analysis time can be reduced and the results will be accurate to Construction Stage Analysis. In this project multistoried reinforced concrete building frames with different number of floors are analyzed using ETABS, and then Construction Stage Analysis of each building model is done. A comparative study of Bending moments, axial forces, twisting moments and shear forces are carried out at every stage of the structural frame. These values are compared with linear static analysis and Construction Stage Analysis. From the values obtained correction factors are derived. From this method we can get results which has a maximum error of 2% and this proves that correction factor can be used as a substitute for sequential construction analysis

CONSTRUCTION STAGE ANALYSIS OF SEGMENTAL BOX GIRDER BRIDGE

Segmental bridge construction is very common in Pakistan. However, the impact ofstructural system changes before and after the completion of segmental bridge construction is achallenge and major concern for construction stakeholders. Therefore, in this study, construction stageanalysis was performed for balanced cantilever construction technique to check the safety andserviceability of the bridge. Through time dependent analysis, considering the construction sequenceand creep deformation of concrete, structural responses related to the member forces were reviewed.Moment reversal was observed in the cantilever segments near the face of the pier. Therefore,maximum compressive and tensile stresses were observed in the top and bottom fibers of the girder,respectively. These stresses were within the AASHTO LRFD limits for construction stage loads.Results demonstrated that the creep moment redistribution started when the structural system changedfrom statically determinate to indeterminate stage. Furthermore, it was concluded that the timedependent deformation of concrete was the governing factor in order to achieve the final designmoments.

On the construction stage analysis of historical masonry vaults

On the construction stage analysis of historical masonry vaults

Effect of Axial Shortening of Column in Building with and without Soft Storey

The construction of tall concrete building became popular. As a result, we can see the problem of shortening of column due to huge loads carry by column .During construction of a tall building, the vertical elements would be subjected to a number of load increments. Each load increment would cause elastic shortening of columns. It will lead to long term creep and shrinkage shortening of such elements. Shortening of column cause effect on horizontal elements such as beams and slabs seriously. The slabs may not be truly horizontal after some time. Beams could be subjected to higher bending moments when connected to outer columns and inner shear walls. These could have certain structural effects and also could affect the nonstructural elements like damage to floor finishes, services etc.so it became important to study column shortening. In this paper we are going to study the influence of column shortening in case of building with and without soft storey once without considering construction stage analysis and once with considering it and also creep and shrinkage effect include in construction stage by using ETABS Software and comparing the effect.

Effect of Column Shortening in Tall Structure

In our country population growth increses day by day, increase in the land costs to satisfy large population specially in urban cities have made a door for construction of tall buildings. To economize land area, building height increased & the construction of reinforced cement concrete structure increases, during which shortening of column is reported which is become more significant with increase in height and impact the strength design and serviceability of the building. If column shortening is not addressed properly, it can impact the serviceability of the building as it impact on structural and non structural elements. So study of shortening of column in tall structure is importanat. In this paper the effect of column shortening in tall structure, in post construction stage analysis in which all loads applied in a single step, construction stage analysis and construction stage with time dependent effect analysis in which dead load, live load are released on building gradually as the construction progresses is carried on different strucutural system like frame, frame-shear wall and tube in tube system using ETABS software. In the analysis dead load, live load, lateral load due to wind load, earthquake load should be considered. The result obtained from this study gives idea about effect of column shortening in different method of analysis with different structural system and varying height of the structure.

COMPARATIVE STUDY OF MODIFIED CONSTRUCTION STAGE ANALYSIS AND CONSTRUCTION STAGE ANALYSIS FOR RC BUILDINGS

A significant difference is found in axial shortening of vertical members in tall concrete buildings when analyzed by Construction Stage Analysis considering the effect of creep and shrinkage as compared to the conventional One Step Analysis method. In Construction Stage Analysis the self-weight of structural members, and a load of brick walls along with floor finishing load, gets added sequentially as construction is carried out. In addition to the above loads, construction loads such as the weight of formwork, the weight of wet concrete, staking of materials, and other construction loads of men and machines get imposed on the structure during construction. Also, stagewise reduction of load due to removal of formwork, material staking, and other construction loads of men and machines should also be considered during the analysis with the Construction stage method. The axial shortening of vertical members of RC buildings was analyzed by the Conventional one-step method, Construction Stage method, considering self-weight along with brick wall and floor finishing load as sequential loads. Modified Construction Stage method-in which in addition to self-weight, brick wall, and floor finishing load, above mentioned all loads that appear during construction, were added, and removed sequentially in the analysis, by taking 20,30, and 40 floor RC building models. Modified CSA gives 2.068% to 20.56% lesser axial shortening in comparison to the CSA method. The study also concludes that the difference of axial shortening between Modified CSA & CSA increases from first to a certain floor, after that it reduces till top floor.

COMPARATIVE STUDY OF MODIFIED CONSTRUCTION STAGE ANALYSIS AND CONSTRUCTION STAGE ANALYSIS FOR RC BUILDINGS

A significant difference is found in axial shortening of vertical members in tall concrete buildings when analyzed by Construction Stage Analysis considering the effect of creep and shrinkage as compared to the conventional One Step Analysis method. In Construction Stage Analysis the self-weight of structural members, and a load of brick walls along with floor finishing load, gets added sequentially as construction is carried out. In addition to the above loads, construction loads such as the weight of formwork, the weight of wet concrete, staking of materials, and other construction loads of men and machines get imposed on the structure during construction. Also, stagewise reduction of load due to removal of formwork, material staking, and other construction loads of men and machines should also be considered during the analysis with the Construction stage method. The axial shortening of vertical members of RC buildings was analyzed by the Conventional one-step method, Construction Stage method, considering self-weight along with brick wall and floor finishing load as sequential loads. Modified Construction Stage method-in which in addition to self-weight, brick wall, and floor finishing load, above mentioned all loads that appear during construction, were added, and removed sequentially in the analysis, by taking 20,30, and 40 floor RC building models. Modified CSA gives 2.068% to 20.56% lesser axial shortening in comparison to the CSA method. The study also concludes that the difference of axial shortening between Modified CSA & CSA increases from first to a certain floor, after that it reduces till top floor.

Comparative Study of Balance Cantilever Bridge and Extradosed Bridge

Abstract: Now a days, in India Balance Cantilever bridges are widely used in hilly region were supporting from the bottom is difficult. The name Balance Cantilever Bridge is arrived due to the application of construction methodology which balances out the cantilever portion. It is one of the most effective methods of building bridges without the need of false work. Balanced cantilever bridges are used for special requirements like construction over traffic, short lead time compared to steel and use local labour and materials. Extradosed bridge is a unique idea bridge between Girder Bridge and cable-stayed bridge. A balanced cantilever bridge with construction stage analysis consideration a model is prepared in the Midas Civil software and analysed, we can see how it considers construction stage analysis with creep & shrinkage effect. The construction stage analysis in the Midas Civil considers shrinkage and creep during construction stages to simulate the construction process of a incremental stage. As most of the literature covers either balance cantilever bridge or extradosed bridge, this paper introduces and attempt to summaries comparative study of balance cantilever and extra dose bridge with its span arrangement, span by depth ratio, prestressing steel etc. Keywords: Construction stage, balance cantilever , extradosed, prestress

Correlation Analysis of Ground Motion Duration Indexes and Nonlinear Seismic Responses of a Long-span Continuous Rigid-Frame Bridge with High-Rise Piers

ABSTRACT To investigate the correlations of duration indexes and the nonlinear seismic responses of long-span continuous rigid-frame bridges with high-rise piers (CRFB-LH), an irregular CRFB-LH was selected as the prototype bridge. A construction stage analysis model was simulated in MIDAS/Civil, where the actual construction process was considered and the internal force state was extracted. After that, a nonlinear dynamic analysis model of the CRFB-LH with the equivalent internal force state was simulated via OpenSees. A bracketed duration and significant duration with a continuous-time interval were selected as the duration indexes. Sixty ground motion records with total duration values ranging from 9.91 s to 300 s were used in the nonlinear dynamic analysis. The correlation between the two duration indexes and the nonlinear seismic responses of the CRFB-LH under total-duration ground motions were analyzed. Finally, the effect of different duration indexes on the nonlinear seismic responses of the CRFB-LH was discussed under 30 long-duration ground motions intercepted according to D b0.1g , D s5-75% and D s5-95%. The numerical results show that the correlations of D s with nonlinear seismic responses are better than those of D b, and the latter heavily depends on the absolute acceleration threshold. D s5-95% is preferred for calculating the total hysteretic energy dissipated (HED) from the CRFB-LH. Additionally, while the amount of total HED is not determined by the total duration, the effective time interval of the ground motion duration under different duration indexes has a significant influence on the total HED.

Horizontal end crack control and load-bearing capacity performance of hollow-type pretensioned girders through experimentally calibrated finite element models

Prestressed concrete girders are prone to the formation of horizontal end cracks during prestress transfer. These cracks propagate and progress extensively in deeper hollow-type pretensioned girders with larger prestressing forces. This study examines the strand-debonding method to eliminate horizontal cracks at the ends of hollow–type pretensioned girders by directly reducing the vertical tensile stresses resulting from the prestress release acting on the strands. Finite element analysis is adopted to model the girder and identify the cracking zone in the cross-section. Furthermore, the load-bearing capacity of the girder is investigated through a four-point bending test using construction stage analysis in a numerical simulation. The numerical results are validated through fabrication of an actual girder with geometrical and mechanical specifications identical to those in the numerical model. The experimental findings match the numerical results; the horizontal end cracks diminish with the application of the proposed method. Furthermore, the study confirms the normal behavior of the girder against vertical loading; the girder can resist the load, similar to a girder with an ordinary cross-section.

Construction stage analysis of a precast concrete buried arch bridge with steel outriggers from full-scale field test

A new type of Precast Concrete buried Arch bridge with Steel Outriggers (PCASO) was developed to maximize the structural efficiency and improve the constructability of a precast concrete arch system buried underground. In this study, a full-scale field test of Precast Concrete buried Arch bridge with Steel Outriggers (PCASO) was conducted to evaluate the strain and stress state and deformation observed on the concrete panels and steel outriggers during the various construction stages, namely, when the panels were being lifted, and when backfill was being placed on the arch in three stages. The field specimen spanned 6 m and was 2 m high. Displacements were observed in both the vertical and horizontal directions during the backfill construction. However, the final position of the arch was achieved when topsoil was placed on the precast panels. The compressive strains observed on the precast panels increased as the soil was being placed. After the backfill was completed and the topsoil was emplaced, the maximum compressive strains measured on the precast panels were approximately 19% of the compressive strength (which was 8 MPa). During the construction stage, the steel outriggers experienced maximum tensile stresses of approximately 300 MPa, which is close to the service stress level of steel (whose yield strength is 413 MPa). Considering that the outriggers were constructed with thin steel plates and there was little stress change during different construction stages, the nominal stress of the thin plate was checked. The calculated nominal stress based on the measured compressive and tensile stresses ranged between positive and negative 25 MPa. A finite element analysis was conducted following the construction stages of the field test using the field parameters. The analytical study demonstrates that the changes in stress and displacement for each construction stage are comparable between the field measurements and the numerical calculations. Overall, this study validated the structural behaviors of the new type of PCASO through field demonstrations and finite element analyses.

Process-independent construction stage analysis of self-anchored suspension bridges

The construction process of self-anchored suspension (SAS) bridges undergoes frequent system transformations and loadings, accompanied by complex strong geometric and contact nonlinear behaviours. The accurate state assessment of such a process generally requires the nonlinear finite element analysis (FEA) to perform a stage-by-stage forward, cumulative calculation based on the principle of incremental superposition. This sort of calculation means that the structural equilibrium of any intermediate state of the process, referred to as a construction stage, must be accumulated from its previous construction loading history, which is susceptible to computational effort and divergence limitations. This paper overcomes these limitations by proposing a direct and fast method that is independent of the cumulative calculation in the analysis of any specified construction stage, in favour of the construction optimization design and uncertainty analysis. The unstrained assembly formats for the typical construction process of SAS bridges are established, and the elements with constant physical quantities as the characteristic parameters are used to describe the various structures, boundaries, loads and their changes during the construction. On this basis, an interactive analysis framework integrating the numerical iteration with the FEA is established to achieve an accurate equilibrium for the construction stages. An enhanced interval-genetic algorithm (IGA) is employed as the optimization engine to smoothly accelerate global convergence. The proposed framework is applied to an SAS bridge under construction, and the validity and performance of this approach are demonstrated by considering the in-field test data.

Stress-Strain State of a Cylindrical Shell of a Tunnel Using Construction Stage Analysis

The work is aimed at research of the stress-strain state of a cylindrical shell of a tunnel using the non-linear static analysis and construction stage analysis. Research is carried out on the example of determining the stress-strain state of the tubing (shells) of the main line tunnel, constructed using a tunnel powered complex (slurry shield). Based on obtained results, a comparative analysis of the computational models with the corresponding conclusions is presented.