Many federal and state statues apply to the employment of construction workers and any construction firm must have an understanding of their workings and implications. As depicted in previous blog posts in response to assigned videos, any construction site can be subject to injuries or death of workers or the public due simply to the nature of the work. From our book, "there are approximately 400,000 reportable injuries to construction workers and more than 1,000 deaths each year in the United States as the result of work-related injuries." Employee orientation and training becomes so important in the construction industry. And not only can project safety concerns affect workers, but damage of materials or equipment, spoiled work, and adverse publicity can be costly side effects as well. Common indirect costs include workers compensation, liability, penalties, and public relations. Ensuring project safety has not only a humanitarian aspect, but many financial benefits are gained as the project does not have to be set back and insurance costs can rise as more accidents occur. Under the Occupational Safety and Health Act, safety inspectors can conduct unannounced site inspections to see if employers are complying with safety standards. Today, OSHA inspectors must be approved by the employer or must first obtain a search warrant.
Here is a video we were assigned to watch regarding building a scientific village at the South Pole.
Planning became extremely important due to the far distance from civilization, freezing temperatures and unusual daylighting throughout the year. Every 90 minutes workers were taking a break at one point in construction to avoid frost bite. The steel framing workers faced unusual and difficult circumstances due to the low temperatures which freeze the steel and actually cause it to shrink. The workers also ran into issues with equipment sometimes not working due to the temperatures.
All construction projects require some amount of field organization to meet the contractually set time schedule, cost budget, and quality requirements. Once construction is underway, the work can become variable in nature. The many diverse elements involved in project completion must be pulled together. Project management can be described as an allocation and efficient use of resources to achieve timely completion within the established construction budget. The resources required are money, manpower, equipment materials, and time. Uncertain and changing conditions, field construction costs and time requirements are usually changing in a project, so skilled managment is a necessity. At the architecture firm for which I interned, our construction administration department was typically under more stress than the design team ever was, as they had to deal with many unforseen issues and disparities in a timely manner. If money was to be lost during the course of a project, it was usually in the construction phase.
There are many scheduling methods for a project, such as the use of bar charts, matrix schedules, and network schedules, which include arrow notation and precedence notation.
The critical path method (CPM) is a procedure used in the time management of construction projects. By identifying each activity, the sequence of the activities and the estimated completion time of each activitiy, the method allows for informed decision making on projects of any size and helps guide the contractor. The preparation of a precedence diagram (left) requires time, work and experience with the type of construction involved.
The bar chart below is a simpler method for project time management than the precedence diagram above; however, it does not show any activity dependencies.
Here is an article regarding the use of e-Builder as a Project Management System utilized by the city of Kansas City, Missouri. This is a "comprehensive project management system for management and tracking of capital improvement projects, including water, sewer, roads, facility construction, parks, and other construction projects." The city looks to achieve more transparency to citizens and increase department efficiency by using e-Builder’s integrated Cost, Documents, Processes, Bidding, Schedule, and Reporting modules.
Least-Cost Project Shortening:
Reducing the length of critical path involves revising the job logic or shortening some of the individual critical activities or both.
As presented in our online task, the video on One Bryant Park in New York City proved to be a multifaceted project, both in the design and construction aspects. Beginning with the fact that this is a sustainable project, all players had to be on-board for such an ambitious green skyscraper. This was a 50:50 joint venture between the Durst Organization and Bank of America, both of whom had strong desires towards sustainability in this project, and the architect Richard Cook was also a major player with the sustainable design. Through the use of natural ventilation, green roofs, the use of frozen water for the A/C system, the water reclamation system, and the new technology in the glass curtainwall to allow light in but reflect the heat, this building is one of the greenest skyscrapers in the world.
The team also sought after a sustainable approach to the construction process as well. Their materials had to be sourced within an 800 km radius to cut transportation costs and energy. About 60% of the steel beams were created from recycled scrap metal. And the slag by-product from producing the steel was utilized in about 45% of the concrete mix, which emits less carbon and makes the concrete stronger. Besides the sustainability aspects of the project, the conditions of building in New York City were interesting as well. The construction site was already very congested and they had to dig a deep foundation of 100', but blasting is forbidden in the city because of the subways below and the nearby historic buildings so they had to work the old fashioned way by digging. Through the use of chisels and excavating machines, the excavation took one year to complete. Deliveries were also a concern in the city since the average load of steel beams being delivered is 23 tons but traffic is such a problem. Typically, large loads had to be delivered early in the morning.
The video also highlighted some situations that arose during construction which the team can't usually predict but must be ready with quick solutions. The weather was a concern a few times during construction as workers had to continue pouring concrete floors in the rain in order to keep pace with the steel structure assembly and the wind postponed the hoisting of one of the largest beams at the top of the building due to the fact that cranes can't control loads laterally so an accident could occur in high winds.
Here is another video highlighting One Bryant Park and 4 Times Square, which was created by the same developer nearby.
The San Francisco Federal Building is another project utilizing more sustainable features, and the video in the link contains some interesting interviews with the major players of the project in which the architect's role and the owner's role are discussed as they relate to not only the design of the building but also the end use of it and the building's role in the community.
As part of our first task, we were to watch this video on the Caltrans building in Los Angeles.
Designed by Morphosis, a very well-known architecture firm, and built by Clark Construction Group, the Caltrans building does not meet the heights of some of the world's tallest skyscrapers, but it is a very unique and intricate building. The design and sustainability aspects of this building and the San Francisco Federal Building (also designed by Morphosis) are quite interesting. I could continue on with the architecture of this project, but focus should be put on the construction element.
It was interesting in the video that the skyscraper was regarded like a "testbed" and that it is a place where they like to "work out new technology, new ideas, and new construction methods" as they try to build "ever taller, faster, cheaper." The video also highlighted the role of the general contractor and his team. The construction process is under high pressure as the GC works "like a traffic cop" to coordinate all subcontractors, scheduling, and costs. The contract contained a $25,000 penalty for everyday the construction goes beyond the scheduled completion date. And besides what is stated in the contract, the GC is constantly responding to issues on site, such as injury or death, weather conditions, mistakes, and crime. The construction site can become something other than intended, like a memorial site for the worker who died, or a media spectacle when the crane was hijacked.
I enjoyed the historical components in the video as well (architectural history was my favorite subject in my undergraduate studies). The invention of cast iron columns replaced the use of thick masonry exterior walls for structure. This started a huge revolution in design and construction due to the fact that with "skeletal construction" the building can be supported from within which freed the facade to be independent and designed separately. This innovation allowed for unlimited height of buildings to be constructed and the interior could then be designed to utilize maximum floor space (more square feet to be rented out).
The structural engineering of this building, although always an important element, was vital in this project due to its location. Because the building is located in an active seismic zone, careful consideration had to be given to the design of the framing in the project. The video went further and described a skyscraper in Taiwan, a location where construction must consider seismic activity and typhoon winds. Steel framing is used to handle any earthquake activity but it is so lightweight compared to the strong winds the building must face, so a braced core with outriggers was engineered. I worked on a project for school in which I had to analyze the Jin Mao Tower in Shanghai, designed by SOM (the same firm who designed the John Hancock Center in Chicago which was mentioned in the video for its innovative structural design).
The building contains an octagon-shaped concrete shear wall core surrounded by 8 exterior composite supercolumns and 8 exterior steel columns. Three sets of 8 two-story high outrigger trusses connect the columns to the core at 6 of the floors to provide additional support. (The number 8 is associated with prosperity in the Chinese culture, which appears in other areas of the design, such as 88 floors. The design also draws on traditional Chinese architecture by utilizing the tiered pagoda form.) Additionally, the steel shafts have shear joints which act as shock absorbers for the lateral forces imposed by winds and earthquakes. The drawing below is one I did as part of the above-mentioned project to illustrate a composition containing both the elevation and a section cut through the tower. Mid-way through the drawing, one can also see a partial floor plan and some enlarged structural details.
Some statistics to note (according to our textbook published in 2005): approximately 80% of construction is privately financed and about 20% is funded through various public agencies. Construction industry employment, when taking into account the production, transportation, and distribution of construction materials and equipment, represents about 12 percent of the total gainful employment in our country.
Major Players:
The Owner: is the instigating party of the project
Public owners: agencies of the federal government, local boards, commissions, authorities. Public projects are built to meet a defined public need.
Private owners: individuals, partnerships, corporations, or various combinations. Most have structures built for their own use and others complete the structure to be sold, leased, or rented to others.
The Architect-Engineer: is the party or firm that designs the project ("architect-engineer" is a term only used in our book and this blog to refer to the design professional because most projects involve architectural or engineering design or combination of both)
The Prime Contractor: also known as the general contractor, is the company that contracts with the owner for the construction of the project.
The Subcontractor: is a construction company that contracts with the prime contractor to perform some aspect of the construction work.
Types of Construction:
Residential: single-family homes, condos, town homes, low-rise apartments, garden-style apartments, and high-rise apartments. Accounts for about 40-45 percent of new construction during a typical year (in 2005).
Building: institutional, educational, light industrial, commercial, social, religious, governemental, and recreational. Accounts for about 25-30 percent of new construction.
Engineering: projects that are planned and designed by engineers, such as highway and airfield, heavy, and utility construction. Accounts for about 20-25 percent of new construction.
Industrial: projects associated with the manufacture or production of commercial products or services. Accounts for about 5-10 percent of annual construction.
Financing:
By Owner
Public: tax revenues, appropriations, or bonds.
Private: typically is banks, savings and loan associations, insurance companies, real estate trusts, or government agencies
By Builder-Vendor: is a business entity thats designs, builds, and finances the construction of structures for sale to the general public.
By Developer: developer firm provides owner with project design and source of financing or developer provides design, finance and construction.
Contract System: prime contrator typically enters into a contract with the owner
Competitive Bidding: typically awarded to lowest bidder; normally required by law for public contracts.
Open bidding: use same proposal form, bids are opend and read publicly, "Hard Bid" approach.
Closed bidding: no prescribed proposal form, no public opening.
Negotiated Contract: owner negotiates a contract with a preselected contractor or small group of contractors.
Construction Contract Types:
Construction Services Only: accomplishment of field construction only.
The Single Prime Contract: entire project is awarded to a single prime contractor.
Separate Prime Contracts: project constructed by several different prime contractors.
Design-Build: both design and construction is contracted to a single firm.
Construction Management (CM):
CM Agency: method of managing design and construction services
CM At-Risk: project delivery of design and construction services
Licensing:
Laws pertaining to construction: zoning regulations, building codes, environmental regulations, building permits, field inspections, safety and health regulation, and the licencing of contractors and of skilled workers in certain construction crafts.
Licensing of contractors not universally required, but many states and local governments do require some or all contractors by licensed.
