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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Engineering Services for Government Infrastructure RFQ No. 07.03.01 - - -8 Based on BHA past experience with this type of design and construction (a total length of 9.23 miles of steel box girder design), we will consider the following key elements during the design phase and plans preparation. D BHA practice is to work closely with the American Institute of Steel Construction (AISC) and steel fabricators in the development of the base and detail designs. This input has been invaluable on past projects in developing concepts that are cost effective, practical and easy to erect. o In detailing the box girders, due to curvature, we will limit the maximum length of the shipping piece. The splice sections will be based on shipping piece size, crane capacities, stage construction and ground restrictions. D Special attention must be paid to constructability during the design phase. A particular area of concern is lateral support of the top compression flange during casting of the deck. If this flange is too narrow or not sufficiently braced; the compression forces induced by casting of the concrete deck could cause out-of-plane distortion. Pouring of the deck shall proceed at full width of the bridge deck, so that all boxes are equally loaded at all time. Also internal lateral bracing will be provided for transportation and erection purposes. o Evaluation of superstructure for construction loads and staged deck placement to minimize tensile stresses in the deck concrete introduced by the structure continuity. o Web thickness as a function of stiffener labor and cost versus cost of web material. o Bottom flange thickness versus longitudinal stiffener. If longitudinal stiffeners are required a possible concept will be using concrete inside the box girders with shear studs over the piers in lieu of expensive longitudinal stiffeners. The concrete stiffen the flange and can be designed to carry a portion of the compressive force in the bottom flange. D Possible use of High Performance Steel, taken into consideration its availability. D It may become necessary to replace the bearings during the life of the structure. Provisions will be made for replacing bearings by lifting the structure by means of jacks at predetermined locations. These locations will be detailed such as to enable easy placement of jacks, and the design shall verify the adequacy of the structure to resist the stresses developed during the lifting operation. Accessibility to the inside of the box girders, safety of bridge inspectors and maintenance personnel: D Interior access to each box girder will be provided through an opening in the bottom flange. D All utilities and conduits, except water main due to possible rupture, will be installed inside the boxes. D Due to the confined space inside the box girders, inspection personnel must exercise great care. Temperature inside the units during summer time can become a serious hazard and cause heat exhaustion. Forced ventilation, using air blower at the openings can alleviate this condition. D A wire mesh door with Self-Locking Device will cover the walkthrough openings to prevent entry of birds. Failure to observe this simple precaution may lead to accumulation of corrosive bird excreta on the floor of the bottom flange. D Interior lighting and electrical outlets will be provided in all boxes. 2.6 Preliminary and Final Boardwalk and Observation Deck Design It is our recommendation that the Boardwalk connecting Town Center Park down to the North Bay Road Pedestrian and Emergency vehicle bridge and Observation Deck be contracted using the Design/Build Method to avoid risk exposure and to shorten the construction duration time. By removing this work scope from the general contractor's work, both the pedestrian/bike/vehicular bridge and Boardwalk can proceed simultaneously and independently assuring the completion date and giving the Boardwalk Design/Build firm sufficient lead time for material purchase and fabrication. The Marlin Team has consulted with Sun Belt Construction Services, an outstanding boardwalk designer, on matters of cost to insure that we have a realistic design/build fees for this project (See inset of similar Boardwalk). ~~~~,