Safety-Critical Decision Making. A construction project consists of multiple components that all have different decision-making processes. For each project, different decisions from the earliest planning stages through construction all have an impact on occupational safety and health (OSH) based on how the hazards are controlled. During the planning stage, the foundation type and material was determined by the constructor. Local topography and owner preferences led to the decision to use a basement instead of a slab on grade. Cast-in-place concrete was used for the basement instead of CMU because it was quicker to install, cheaper, and complied with neighborhood codes. During the design and procurement stage, more decisions were made regarding the house’s structure and construction methods. For the initial excavation, the constructor decided to have the sides benched and sloped back instead of temporarily shored. This was due to cost, schedule, and space provided to workers in the pit. The excavation area was also set to be 4 feet past the wall faces in order to increase safety and available room for workers. The size of the site also permitted overexcavation. After the foundation walls were completed, the excavation was backfilled 3-4 feet. Since workers were not working at as much of a height, no fall protection was needed. This also was done to increase worker productivity. Floor trusses were used instead of traditional joists to ensure higher build quality and allow for easier integration of the mechanical systems. Pre-fabricated trusses were used for the roof to save money and time on installation. During the construction phase, the constructor decided to have a painted warning barrier six feet from the edge serve as leading edge fall protection. This was cheaper and quicker than installing a netting system or tie-off points and still complied with OSHA guidelines. Exterior wall construction was done by building inside the six foot safety barrier and then moving the finished wall to the outside. This decision was made due to worker productivity, safety, and cost. Cost also influenced the decision to lift materials manually as opposed to using a mechanical lift. The constructor said that using a mechanical lift would be cost prohibitive for a residential project. When installing the roof trusses, workers did not use fall-arrest systems. Instead, workers used ladders and scaffolds from the inside of the house. Until all the trusses were secure in place, the individual trusses would not...
Safety-Critical Decision Making. A construction project consists of multiple components that all have different decision-making processes. For each project, different decisions from the earliest planning stages through construction all have an impact on occupational safety and health (OSH) based on how the hazards are controlled. During the planning stage, a two-story layout was chosen for the building. A one-story layout was preferred by the hospital, but it would have a large footprint. A layout with three stories or more would be more expensive to build and the stairs would be too much for patients and hospital staff. After the layout was determined, the project team was able to create conceptual drawings, hire a pre-construction services firm, and hold constructability reviews to help make decisions about the building design. For the exterior façade, pre-cast concrete panels were chosen over brick and metal sheeting. This decision was made because of the panels’ low cost, constructability, and commonality with other buildings in the region. Courtyards were included in the design to maximize natural lighting into the building and allow outdoor space for patients. Having the courtyards completely enclosed by the building enhanced patient security and privacy. The courtyard walls consisted of the same pre-cast panels as the exterior of the building. One option for the courtyard walls was to have the panels go up to window sill height with siding continuing up to the full building height. The architect did not like how this option looked on the design, so the panels were designed to full building height. The design of the building also included rooftop HVAC units. Instead of leaving the rooftop units exposed, the owners wanted to have them screened from view. During the design and procurement stage, the project team went into greater detail on the pre-cast exterior panels. The panels on the exterior of the building were all designed to be full building height and rest on the footing. This decision was made with input from the CM and panel designer. Using full-size panels where possible allowed for fewer deliveries, fewer crane lifts, lower cost per panel, and quicker installation. Installing the panels clockwise around the building instead of from the inside out meant that the overall lifting schedule was shorter. For the cranes, an open path was left for the big courtyard but not for the two smaller courtyards. The open path permitted a smaller crane to be moved inside the larger courtya...
Safety-Critical Decision Making. The owner wanted the server room to have a gas-based fire suppression system. These systems are typically more expensive to install and maintain, but they are quicker to extinguish fires and will not damage sensitive electronic equipment in the process. A traditional water sprinkler system was also installed alongside the gas system. The gas for the fire suppression system is stored in 30 tanks in the basement of the building from where it is piped up into the server room. The tanks are secured into place with a steel frame. A platform and guardrails were installed on top of the tanks for workers who were installing actuator valves on top of the tanks. This greatly reduced fall risks for those workers installing the valves. The high ceiling of the server room made manual lifting of the pipes impossible. Engineering calculations of the gas system advised the pipes be upsized to account for friction loss.
Safety-Critical Decision Making. A construction project consists of multiple components that all have different decision-making processes. For each project, different decisions from the earliest planning stages through construction all have an impact on occupational safety and health (OSH) based on how the hazards are controlled. There were two components associated with the haul road: transit issues and maintenance. For workers and equipment using the road, stone and grading was used on the road as an engineering control to prevent falls, trips, and slips. Communication as an administrative control was used to prevent workers being struck, caught in, or compressed by objects or equipment. Communication was also used extensively during haul road maintenance in order to keep the road open and accessible. Temporary bridges were used in this project to allow workers and equipment to traverse the site’s wetland location. The bridges were designed wider than normal to allow workers more room to safely cross alongside vehicles. Communication and signage were used as administrative controls to alert workers to traffic on the bridge. Temporary barricades served as fall protection for workers on the bridge. Maintenance of traffic was important for the public side roads where construction vehicles access the site. In order to keep the multiple site access points safe, signage and barricades were used to reduce the risk of workers being struck by object or equipment. These controls were also used to keep the flow and safety of construction vehicles entering and exiting the site.
Safety-Critical Decision Making. A construction project consists of multiple components that all have different decision-making processes. For each project, different decisions from the earliest planning stages through construction all have an impact on occupational safety and health (OSH) based on how the hazards are controlled. To address demands for increased seating capacity for football games, the university had to decide to either expand the old stadium or build a new one. The decision to expand was influenced by the facility’s current seating capacity, ticket revenues, and football recruitment. The expansion project was managed by the university administration and athletic departments. To meet targeted seating capacity, the expansion plan included upgrading both the east and west stands. The west stands were to be expanded first because of cost and an existing aquatic center located directly behind the east stands. The design for the new west stands was influenced predominately by the available space. A parking deck located behind the west stands prohibited building a single deck structure. Demolition of the aging concrete stands and construction of new steel lower and upper stadium decks was the chosen configuration for the conceptual drawings. Using these drawings, structural engineers came up with load calculations to determine the support system needed for both decks. With the limited space between the rear of the stadium and the parking deck, cantilevers were chosen to support the decks. Building on top of the garage was considered, but load calculations for the garage showed that the structure could not support the extra load. The university preferred to use concrete for the new stands, but the extra costs and structural loads made this option unfeasible, so steel was used instead. After creation of the design development drawings, the university worked to determine a construction schedule that would work with the football schedule. The construction was originally divided into three phases, but the CM who won the bid proposed a plan to construct the new stand in two phases without interfering with the football schedule. In order to erect the steel structure for the new stands, the project team had to decide where to place the crane. The site around the stands restricted crane placement to either across the creek, behind the garage, or on the track inside the stadium. Building a temporary crane pad on the track was chosen because of cost and to allow the parking deck to remain...
Safety-Critical Decision Making. A construction project consists of multiple components that all have different decision-making processes. For each project, different decisions from the earliest planning stages through construction all have an impact on occupational safety and health (OSH) based on how the hazards are controlled. The decision to install an economizer on the second unit was made after the procurement of the plant’s capital project budget. Data from the existing unit and the facility’s operations demonstrated that an economizer would have long-term cost-saving benefits for the plant. Following the approval of the project, the project team needed to decide whether to coordinate the installation with a turnaround or shutdown period. The scope of the project required too much time to take place during a shutdown, so the project team decided to coordinate the project with the next turnaround period. The project engineer was familiar with coordinating other projects during turnarounds. The owner would have preferred to have bolts used for tie-in of the ductwork however the connections had to be welded instead in order to prevent oil leaks. The design was further developed by determining crane requirements and specifics about the economizer’s steel support structure. While the economizer height was 70ft, a 100ft crane was used since the top part of the 100ft stack would have to be temporarily removed to install the economizer and tie it in. Off-site fabrication of the steel structure was chosen because of the accelerated schedule and to isolate construction from the rest of the plant’s operations. Before the project team could determine specifics about the pre-fabrication, they had to decide on the delivery method from the fabrication site to the plant. The economizer’s planned location was accessible by a small roadway, so a truck would be used to deliver the frame. An overhead electrical line was identified along the roadway that needed to be addressed before crane placement. Since the line was not in use, it was removed. Based on the capacity of the delivery trucks, the project team determined that the frame could be pre-fabricated and delivered in one piece. The economizer was connected to the frame with four bolts. Compared to welding, bolting in the economizer minimized the time workers needed to spend at heights installing the economizer. Man-lifts were used during the tie-in of the economizer since scaffolding required too much time for assembly and disassembly. It was al...
Safety-Critical Decision Making. A construction project consists of multiple components that all have different decision-making processes. For each project, different decisions from the earliest planning stages through construction all have an impact on occupational safety and health (OSH) based on how the hazards are controlled. During the planning stage, details about the foundation were determined by the constructor. Cast-in-place concrete was used for the basement walls instead of CMU because it was quicker to install, cheaper, and complied with neighborhood codes. During the design and procurement stage, more decisions were made regarding the house’s structure and construction methods. For the initial excavation, the constructor decided to have the sides benched instead of temporarily shored. This was due to cost, schedule, and space provided to workers in the pit. The size of the site also allowed for overexcavation to give workers more room to work safely. The excavation was backfilled after the first floor deck and exterior walls were completed. Floor trusses were used instead of traditional joists to ensure higher build quality and allow for easier integration of the mechanical systems. Pre- fabricated trusses were used for the roof structure to save money and time on installation. Using pre-fabricated trusses also meant that workers spent less time on the roof during installation. During the construction phase, exterior wall construction was done by building on the finished floor deck and then moving the finished wall to the outside. The xxxxx end and interior trusses were lifted into place with a small crane. When installing the roof trusses, workers did not use fall-arrest systems. Instead, workers used ladders and scaffolds from the inside of the house. Until all the trusses were secure in place, the individual trusses would not be able to support the lateral loads if a worker fell and was tied off to that truss. Trusses were secured with blocking that was installed on the ground and secured and connected while at height attached to the crane. Once all the trusses were secured and laterally stable, disposable tie-off brackets that complied with OSHA were used as worker fall-arrest systems. A telescoping forklift was used to lift materials onto the roof where they were installed manually by workers. No fall protection was used for this part of the construction.
