The land surveyor’s role in development is critically important in answering these questions.
The land surveying profession goes back thousands of years and today covers a multitude of disciplines from hydrographic surveys both above and below bodies of water to high altitude aerial surveys, from the small neighborhood lot survey to establishing the Global Positioning System (GPS) for navigating around the world as well as guiding our cell phone directional apps.
With construction and development now making a comeback after this past recession, one area of land surveying coming back is Construction Staking Services for new residential tracts of homes, high rise buildings, schools, landfills, industrial parks and shopping centers. During site development, the land surveyor plays a critical role. The land surveyor takes the engineer’s/architect’s design shown on their plans and places (stakes) their correct location on the ground so the construction sub-contractors can place the buildings, roads, fences, electrical and other underground utilities, etc. in their correct location. If not for the surveyor, there would be no telling exactly where that building should be built or how far or deep that tunnel should be dug!
The following is an example of the typical involvement of the land surveyor and how he would interact with a civil engineer and/or architect as it relates to the design and construction of a residential housing tract, shopping center or industrial park.
Engineering Design Survey
The beginning of a new constructible project typically begins with an Engineering Design Survey. This survey is typically requested by the civil engineer in charge of designing a new project. During the design survey, the Professional Land Surveyor works closely with the civil engineer to gather the “as-built” existing site conditions in and around the proposed project. It is the surveyor’s responsibility to be the engineer’s “eyes” while performing this survey to gather all of the controlling elements for his design. Some of those controlling elements or features will be ascertaining:
• The condition of the adjacent streets
• What is the sidewalk gradient? Is it ADA compatible? Is it in need of replacing?
• Are there already driveway access areas from the streets to the site?
• Is there evidence of electrical/gas/sewer/water utilities servicing the site?
• What is happening around the perimeter of the site? Are there walls/fences that follow or cross over the property line and what is their condition?
• Is there evidence of underground contamination, dumping or site access from an adjacent property?
• Is this site on a hillside and not a buildable lot?
This information along with site photos and public record documents gathered at the local agencies will assist the civil engineer in the workable design of this project.
Construction Staking Phase
Rough Grade Staking:
Once the site has been designed by the civil engineer and has gone through submittal, plan check and approval at the local agencies, the property owner/engineer can then pull a grading permit. This enables the beginning of construction. The surveyor is first called out to Rough Grade the project.
This series of staking is exactly what it is called, Rough Grade Staking. This defines the location of the site improvements with their respective reference to the location and final grade elevation. This is done for the construction of slopes, building outlines, parking lots and roadways. This set of staking enables the contractor to grade and prepare the site for the next sub-contractor to come in and build/install his portion of the site improvements.
Site Layout Staking:
Once the site has received inspection and approval from the local agency, the contractor can move right into the various stages of construction of the underground utilities, retaining/screen walls if required, buildings, site lighting and parking lot/street paving.
This phase, called Site Layout Staking, typically begins with those features that are underground such as sanitary sewer lines, storm drain lines, water lines, electrical lines etc. Sanitary sewer and storm drain lines are based on “gravity” flow so those lines need to be staked and graded per the engineering plans to be built correctly to generate positive drainage out to the existing utilities in the streets. The surveyor’s responsibility is to field verify that the sewer and storm drain pipes do not conflict (run into) other underground utility pipes if and where they may cross, as well as to ensure the correct tie-in point in the street maintains positive flow.
Water and gas lines are a “pressure” based lines and can be pumped upstream if needed or adjusted to go over or under other underground utilities without affecting the flow of the water or gas. The remaining utilities (electrical, telephone, cable) can be staked according to the engineered plans and may have a note as to how deep to place the utility to maintain a minimal depth of cover for protection.
Once all underground utilities are installed the above ground features are staked for construction. The building corners are staked along with any interior grid lines throughout the building. You will typically see this in long industrial buildings or high rise construction. These grid lines are used by other contractors to precisely place those columns, building walls, electrical and/or other utilities that are not located near the outside walls of the building.
While this is happening, other items are being staked onsite such as fire hydrants, curb and gutter, walls/planters, catch basins and area drains to name a few. As the project is coming to a close, paving support staking may be needed to place the aggregate base prior to the placement of the asphalt. This thickness is critical and requires a surveyor’s certification at times due to the fact that drive isles for truck deliveries need a thicker paving section (base aggregate and asphalt pavement) to accommodate the weight of the truck. The drive isles for automobiles do not need that much thickness.
Just as important is the ADA Accessibility from the handicap parking to the entrance of the building, which sometimes crosses a drive isle. There are strict guidelines when constructing these pathways and ramps. A wheelchair path of travel cannot have more than a 2% gradient or “cross fall,” so this is monitored as well as the pathway gradient from the parking stall to the building entry.
Any time during the Construction Staking Phase, the surveyor may be required or asked by the local agency inspector to “certify” that a particular underground utility, curb or building form, retaining wall/building footing or even handicap ramp or path of travel is certified that they comply with the approved engineered plans. This has become a common request to assure that all construction is built per the design standards governed by the relevant state or local agency prior to being open to the public.
The Critical Role of Land Surveyors
Each project and site is different, so this is not a complete list of all areas that fall within Construction Staking. But this should give you a taste of how important the surveyor’s role is and how closely we work with the civil engineer and architect. It is always best to consult with the surveyor, civil engineer and architect to make sure that they understand your ultimate vision and that all are on the same page so to speak.