DESIGN OF AIRPORT TERMINAL AND CONTROL TOWER VARSHA SIEURAJSINGH

INTRODUCTION A new regional airport is planned, in Trinidad & Tobago, to support the growing economy and improve transport links. The primary requirements are for an entirely new terminal building and a new control tower, with an outline design being required for both structures. Group 12 has been appointed as the structural engineering consultant to the client.

AIMS To prepare preliminary designs of structural solutions for both the terminal building and the control tower. To compare the alternative design solutions and to select the most viable designs. To present a clear recommendation to the client about the design solutions selected with reasons for our choices.

PROCESS To present the alternatives and to state the bases for their selection. To describe the methodology for the selection of the best alternative. To finally present the best options to the client.

PROJECT APPROACH HOW DID WE SELECT THE BEST ALTERNATIVE? 1. DESIGN STRUCTURES – THIS includes THE preliminary calculations and drawings 2. COMPARE ALTERNATIVES BASED ON FINANCIAL, ENVIRONMENTAL, STRUCTURAL AND AESTHETIC FACTORS 3. ASSESS STRUCTURES BY PERFORMANCE EVALUATION MATRIX AND COST COMPARISON 4. CHOOSE ALTERNATIVE WITH THE HIGHEST PERFORMANCE POINTS AND ALSO WITH THE LOWER COST 5. PRESENT BEST DESIGN OPTION TO CLIENT

Terminal Building A “Pier” layout for the terminal building was chosen by the design team. - It ensures a regular, symmetrical and simple shape. All of which aid in the feasibility and functionality of the design. - The pier design offers high aircraft capacity and simplicity in design. From this common layout two Structural options were considered for the Terminal design.

Airport Terminal Option 1 For the first design option, the primary material used was Reinforced Concrete. Concrete was utilized because of its relative inexpensiveness and adaptability. The structural system employed was a MRF ( Rigid Moment Resisting Frame). The MRF was utilized to effectively resist vertical loads and also seismic loads which are prevalent in Trinidad. The foundation type selected was a pad footing foundation with tie beams.

STRUCTURAL SYSTEMS Moment Resisting Frames consist of beams and columns connected by rigid joints. The type of MRF utilized for the terminal building was a Ductile R.C. frame. This subtype of RC frame was adjudged to be sufficient in resisting lateral loading, and thus was suitable for the Terminal design.

GRAVITATIONAL LOAD PATH

LATERAL LOAD PATH

FOUNDATION PLAN: OPTION 1

GROUND FLOOR LAYOUT: OPTION 1

1ST FLOOR PLAN: OPTION 1

ROOF FRAMING PLAN: OPTION 1

ELEVATIONS: OPTION 1

Conceptual View of Option 1

Airport Terminal Option 2 For this option, Structural steel was the material selected. Structural steel is tough – that is, it has both high strength and ductility. Steel structures are well suited to having additions made to them. Steel frames that are properly maintained will last indefinitely

STRUCTURAL SYSTEMS The foundation used for this terminal was a pad footing foundation with tie beams. Composite floor decking was used for the flooring system in this terminal. Also, a truss system was used to support the roof. MRFs were also utilized in the structural steel design, ensuring that strong moment connections were formed equally in both the x and y directions.

FIRST FLOOR PLAN: OPTION 2

ROOF FRAMING PLAN: OPTION 2

OPTION 2: ELEVATIONS

CONCEPTUAL VIEW OF OPTION 2

CONTROL TOWER OPTION 1 For this option High strength reinforced concrete was selected as the construction material (30N/mm2). The use of high strength concrete permits the design of a stable, economic and space efficient, high rise structure. The structural system chosen, utilizes a combination of moment resisting frames and a shear wall core to resist axial and lateral loads respectively and also to decrease sway.

Structural Systems A Moment Resisting Frame was selected to resist mainly gravitational loading and some lateral loading. A shear wall core, was implemented to resist major lateral loads, which would be significant due to the effective height of the Control Tower. For the foundation, a combination of raft and pile system was utilized to ensure stability.

LOAD PATH DIAGRAM: OPTION 1

Structural layout of Option 1

CONTROL TOWER OPTION 2 For this option S355 high strength, structural steel was used. Steel structures are highly suitable in areas subjected to earthquakes, as steel allows the structure to absorb part of the kinetic energy produced by the earthquake in the form of plastic deformation. Moment resisting frames and a shear wall system was used to resist both vertical and lateral loads. The foundation used was a combination of a raft and pile system with R.C. pedestals.

LOAD PATH DIAGRAM: OPTION 2

Structural Layout of Option 2

SELECTION OF BEST ALTERNATIVE 1. ECONOMIC ANALYSIS: Analysis and calculations were done to estimate quantities of material required for the structures. Basic rates were applied to the quantities to arrive at a preliminary costing for the structures. Percentages were added to account for additional formwork, services and architectural considerations. A total preliminary cost was then calculated for each option, arriving at the respective estimates.

SELECTION OF BEST ALTERNATIVE 2.PERFORMANCE EVALUATION MATRIX USED TO EVALUATE THE FOUR ALTERNATIVES The structures were evaluated based on various criteria such as material properties (ductility, stiffness, fire resistance), constructability as well as economic costs. Each structure was given a rating of either ++,+,0 or - if performance was very good, good, neutral or bad respectively.

SELECTION OF BEST ALTERNATIVE 3. QUANTITATIVE CONSIDERATIONS FOR ARRIVING AT FINAL CHOICE Cost – refers to preliminary costing. Amount of materials – refers to quantity of material used. Total loading – refers to the total load of building, this affects stability, sway and the size of foundation.

SELECTION OF BEST ALTERNATIVE 4. QUALITATIVE CONSIDERATIONS FOR ARRIVING AT FINAL CHOICE ENVIRONMENTAL SUSTAINABILITY This refers to whether the materials can be recycled or whether they are sustainable. SITE ENVIRONMENTAL IMPACT This refers to the impact which the materials and construction has on the environment inclusive of the waste produced as a result of construction.

SELECTION OF BEST ALTERNATIVE ASSURANCE OF HIGH SAFETY LEVEL This refers to whether the structure would better human life protection in case of accidental damage. EASE OF CONSTRUCTION This refers to the relative amount of labor, time and material taken to construct the structure.

RESULTS OF COMPARISON ECONOMIC ANALYSIS STRUCTURE TOTAL COST ($TT) 1. CONCRETE TERMINAL 131,471,629.77 2. STEEL TERMINAL 230,688,189.40 3. CONCRETE CONTROL TOWER 19,067,135.91 4. STEEL CONTROL TOWER 26,695,701.15 Both the concrete terminal and concrete control tower are the most feasible options based on economic cost. The steel terminal is 75% more than the cost of the concrete terminal and the steel control tower costs 40% more than the concrete control tower

PERFORMANCE EVALUATION MATRIX CRITERIA 1. CONCRETE TERMINAL 2. STEEL TERMINAL 3. CONCRETE CONTROL TOWER 4. STEEL CONTROL TOWER STIFFNESS ++ DUCTILITY + SWAY N/A FIRE RESISTANCE SIMPLICITY AND EASE OF CONSTRUCTION IMMEDIATE CONSTRUCTION COSTS - CONSTRUCTION TIME AND FEASIBILITY LOW MAINTENANCE COSTS

PERFORMANCE EVALUATION MATRIX CRITERIA 1. CONCRETE TERMINAL 2. STEEL TERMINAL 3. CONCRETE CONTROL TOWER 4. STEEL CONTROL TOWER SITE ENVIRONMENTAL IMPACT - + CONSTRUCTION FLEXIBILITY LOW MAINTENANCE COSTS ++ ASSURANCE OF HIGH SAFETY LEVEL ENVIRONMENTAL SUSTAINABILITY TOTAL LOAD TOTAL MATERIALS USABLE AREA

PERFORMANCE EVALUATION MATRIX CRITERIA 1. CONCRETE TERMINAL 2. STEEL TERMINAL 3. CONCRETE CONTROL TOWER 4. STEEL CONTROL TOWER LEAD TIME ++ TOTAL 17 12 Both the concrete terminal and concrete control tower score higher on the performance evaluation matrix

RESULTS OF COMPARISON The table below gives a summary of the review of the main objectives of the design. A YES indicates that the objective was satisfied whilst a NO indicates that the objective was not fulfilled. OBJECTIVES CONCRETE TERMINAL STEEL TERMINAL CONCRETE CONTROL TOWER STEEL CONTROL TOWER FINANCIAL YES NO CONSTRUCTABILITY ENVIRONMENTAL STABILITY GRANDEUR / ICONIC

CONCLUSION After careful examination of the different performance evaluation criteria and economic analysis, it was determined that both the concrete terminal and concrete control tower design options would be the structural solutions which best meet the client’s specifications. We recommend the client advance to the next stage in the design process using both concrete options.

QUESTIONS?

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