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Any use of this work in whole or in part shall respect the moral rights of the author to be recognized and reflected in good faith and without prejudice to the meaning of the content and the original authorship. However, the famous structural systems used for skyscraper design and construction are steel and concrete structures as wood, stone and masonry cannot be used in tall buildings.
INTRODUCTION
- Research Background
- The skyscrapers importance
- Skyscraper drawbacks
- The best materials for constructing skyscrapers
- Advantages of Steel structures
- Disadvantages of steel structures
- pros of concrete structure
- Cons of Concrete structure
- Objectives of research
- Research questions
- Scope of research
- Significance and motivation of the study
55 floors) in Dubai from reinforced concrete and steel using ACI 318 – 19 requirements and to identify the differences between the structural elements (columns, beams and slabs) in the two towers. What are the appropriate plans and member sections for high-rise reinforced concrete and steel buildings to withstand seismic and wind loads in Dubai. What is the estimated budget for construction of reinforced concrete skyscraper and steel skyscraper to resist earthquake and wind loads in Dubai.
What is the period for the construction of the reinforced concrete skyscraper and steel skyscraper to withstand the earthquake and wind load in Dubai. Carrying out structural analysis and design of two skyscrapers consisting of 55 floors in Dubai, made of reinforced concrete and steel, to resist seismic and wind loads, to compare the suitable structural elements for both tall buildings. To estimate the cost of the construction of the steel and reinforced concrete high-rise buildings, compare the budget of both buildings.
To estimate the construction duration of steel and reinforced concrete tall buildings, compare the budget of both buildings. This research is so important as it compares the design and analysis results of steel structure and reinforced concrete structure for a 55-story skyscraper in Dubai, evaluates the cost to build both tall buildings to know which one is cheaper , estimates the total construction time of the reinforced concrete skyscraper and the steel skyscraper to distinguish the faster one.
LITERATURE REVIEW
- Introduction
- Seismic load on buildings
- Wind load on tall buildings
- Wind-Design of Skyscraper
- Torsion irregularity
- Rating P-Delta influence on skyscrapers
- Evaluation of Wind-output Dislocation of Structures with several horizontal
- Investigation on the Dynamical properties of low-weight Steel Housing
- Sustainability of Concrete Structures
- Sustainability of buildings made of steel
- Analysis of cost and seismic performance of skyscrapers in UAE through
In addition, buildings will be classified according to irregularities according to their structural formations. there are horizontal and vertical irregularities, and the types are listed in Table 12.3-1. The ratio of torsional irregularities is calculated according to the equation:. However, full details of ASCE 7-22 seismic loading will be presented, as the analysis and design of concrete and steel skyscrapers are done using it. The results of the analysis of several bracing models showed that different bracing schemes at multiple positions of the building can be effectively used to reduce the extreme bending moment in the columns due to lateral force (wind).
In all examined buildings, the rotation-irregularity constants increase by decreasing the number of floors, i.e., extreme irregularity constants occur for single-story buildings. Floor rotations increase proportionally with the number of floors, i.e. maximum floor rotations occur for higher floor numbers. However, in shear walls other than the double system, the largest displacement in the floor is placed within the middle third of the height of the structure.
About 50% of the energy involved in the production of combustibles can be reused for heat among other purposes. A reduction in the dead weight of the structure was noted, as well as a lower value for overturning moments for the UHPC structure compared to a high-strength concrete structure, resulting in cost savings in foundation design.
RESEARCH METHODOLOGY
- Introduction
- Research Strategy and Approach
- The design codes and Material properties
- Seismic load factors, and other loads values determination
- Post tension slab design by CSI Safe 2020 program
- Selection of steel member dimensions
- Using Microsoft Excel to compare the analysis results
The primary structural system selected to withstand the lateral loads (seismic and wind) consists of columns and sliding walls that can be used for elevators and stairs (two from the 1st floor to the 20th floor), (one from the 1st floor to 40th floor) and the last (from 1st floor to 55th floor) as shown in the drawings. The design strips consisting of column strip and center strips are defined for the post tension plates in X and Y direction. However, the advantage of defining the design strip is that the ETABs and Safe programs use them when locating the cables and steel reinforcement.
The analysis and design is carried out, as a result there are some beams, columns and walls did not pass the design with the initial selected dimensions. It provides great detail for the design and analysis, generating drawings, sections, tables for steel reinforcement, tendon profile, number of strands, analysis results for each load combination and reactions. Similar steps done in the ETABS program are followed here in a safe program by defining the material properties, loads, load combination, design strips, drawing the tendons, checking the model and analysis and design.
Regarding the design and analysis of the high-rise steel building, the ETABs program is set to select the structural elements (steel columns, main and secondary beams) automatically by defining automatic lists consisting of several sections from the ETABS tables that are from the code. so ETABS selected specific members based on different loads, dimensions, building height...etc. For comparison and preview of the results, Microsoft excel was used as shown in chapter 4 to compare story lateral loads (KN), maximum story displacement (mm), maximum story movements (unitless), story shear force ( KN), overturning moments (KN.m) and story stiffness (Kn/m), duration and total cost for concrete and steel tall buildings by drawing the diagrams shown in unit 4.
RESULTS AND DISCUSSION
Final computer design output
Design and Analysis results for Steel skyscraper
Discussion of composite columns sizing
Discussion of main beams sizing
Discussion of secondary beams sizing
Discussion of bracing at external elevations
Analysis results for the reinforced concrete skyscraper and steel
Comparison charts for the analysis results for the concrete and steel
Discussion of Auto Lateral loads in steel and concrete buildings
Discussion of maximum storey displacement
Discussion of Story drifts of concrete and steel tall buildings
Discussion of overturning moments and shear forces
Discussion of story stiffness
Calculation of Cost of steel skyscraper
To calculate the total weight and cost of secondary beams, the weight of W 12 x 130 is 130 kg/m and the length of each secondary beam is 6 m. There are several sections selected for design from the auto selection list, which are mentioned in the table below with number of pieces, total length of each type and weight in KN, then the weight converted to kg.
The Cost calculation of concrete skyscraper
Discussion of cost comparison
Roughly Construction Time estimate for construction of the reinforced
Roughly Construction Time Estimate for construction of the steel
Total construction duration of steel high-rise building 410 days The above time estimate excludes Authority approvals, fabrication and foundation.
Discission of Time of construction
Therefore, the time estimate for the construction of a concrete skyscraper is approximately one and a half times less than that of a steel structure.
ETABS design output for one of the shear walls in the skyscraper
CONCLUSION AND RECOMMENDATION
Conclusion of Structural analysis and Design results
Conclusion of Lateral loads results
Conclusion of Maximum Story displacement
Conclusion of maximum story drifts
Conclusion of maximum shear forces
Conclusion of maximum overturning moment
Conclusion of maximum story stiffness
Availability of Raw materials
Conclusion of construction duration comparison
The answers to the research questions
After conducting many design and analysis tests of the high-rise steel building, as well as in relation to the columns, it is found that the normal steel sections did not pass the design due to the lateral height loads (seismic and wind loads). Therefore, two composite columns which consist of reinforced concrete and embedded steel section I pass the project. The supporting, main and secondary beams are steel W sections of different sizes as explained in Chapter 4.
The Deck Sheet consists of corrugated metal sheet, shear bolts and C 60 concrete as shown in the appendix. The cost calculation and comparison excludes the cost of foundations, stairs, elevator and finishing materials. However, the cost calculation and comparison made after calculating the total price of reinforced concrete and steel buildings with 55 floors, which have the same dimensions and are subject to seismic, wind, live and dead loads.
The results of the cost comparison show that the total budget for the construction of the steel skyscraper cost is AED, while the total budget for the construction of the concrete skyscraper cost is AED, and it means that the total cost of steel building is more than 3.4 times the cost of concrete building . The estimated total duration to construct the above steel skyscraper is 410 days, while the period to construct the reinforced concrete tall building is 600 days.
Recommendations
Areas of upcoming researches
This study deals with finding the appropriate design and member parts for concrete and steel tall buildings, besides comparing the cost of both buildings. Comparison between the fire resistance of steel and concrete buildings Comparison between the durability of steel and concrete buildings. Seismic performance and cost analysis of UHPC tall buildings in the UAE with ductile bonded shear walls.
The results below for Post tension plate and design for level 20 of SAFE-CSI rev.20.
