Our geotechnical engineers and environmental scientists regularly work on K-12 school projects, including developing new sites, replacing existing schools and rehabilitating historic buildings. These projects are critically important to our communities, and they often bring specific challenges for the engineers, contractors and owners involved.
How will the conditions below the surface affect a K-12 project? It’s hard to plan for what you cannot see; and there are many geotechnical and environmental considerations that can affect K-12 facility designs and budgets. Identifying these considerations early on, during planning and cost-estimating, can help prevent cost overruns. An early discussion with a geotechnical engineer and environmental consultant during bond planning can help identify some of these considerations and be used to develop realistic project cost-estimate.
Our team has worked on dozens of K-12 projects, ranging from small pavement rehabilitation projects to large multi-story facility construction projects. This experience gives us an in-depth understanding of some of the geotechnical and environmental considerations that can help manage risk and budget. Below are some key subsurface considerations common to K-12 projects. These five suggestions can help you manage risk and cost when incorporated into planning efforts.
1. Special occupancy structures require special seismic considerations
According to International Building Code requirements, special occupancy structures like schools require seismic evaluations. But seismic design efforts and costs can be tailored to the specific site and structure of the building. For retrofit projects, focusing seismic evaluation and design on specific concerns is more cost-effective than a generalized evaluation.
Seismic codes are changing. In general, these more rigorous standards are making it more likely that seismic effects below ground (liquefaction, slope instability, lateral spreading) will be experienced as a result of design-level earthquakes. Mitigating liquefaction, seismic slope instability, or lateral spreading requires special analysis and ground improvement or deep foundations. Understanding what design standards apply and what type of seismic effects to expect can be useful during bond planning, to help develop more realistic cost-estimates. For most sites, our geotechnical experts can use our understanding of local geology to help develop a preliminary understanding of seismic risks without performing any on-site investigation.
2. Separate pavement designs according to their use to develop more realistic estimates
Different pavement areas can be designed using different standards. Heavily used areas like bus loops, delivery areas, and routes to trash enclosures should be designed using durable and wearable materials (like high-density pavement) and thicker pavement sections. However, those specifications and materials do not necessarily need to be used in areas that require less durability, such as parking areas. This can lower design, construction, operation and maintenance costs for the other areas. Because of the lower durability requirements, parking areas are ideal locations to include permeable pavements to help with low-impact design requirements.
3. Manage change orders by budgeting for earthwork construction observation
Earthwork is an area where change orders can be frequent, as excavation may reveal that actual subsurface conditions vary from the design conditions (even if conditions don’t really vary, the contractor may claim that they do). Having a representative of the geotechnical engineer of record on site during construction to provide earthwork construction observation services can help. Keeping an accurate record of variations in subsurface conditions can help provide real-time solutions for design changes—changes that could hinder construction and the structure’s long-term integrity if not addressed.
4. Time earthwork for dry season or budget for contingencies
Working backward from the target opening date often means scheduling earthwork for the winter. In areas that receive a lot of winter precipitation soils are often moisture sensitive, so conducting earthwork in the winter can be problematic and costly. If earthwork can be scheduled during drier months, it can save a lot of money. If the project schedule is not flexible and earthwork must occur in the winter or spring, there are options that can help keep the project on track, but most of them lead to higher costs. In this case, a contingency for wet weather earthwork should be included in the project budget.
5. Understand history when developing or redeveloping a site
There are often costly surprises hidden underground. There may be serious environmental contamination from previous site uses, such as an underground storage tank or a former industrial area with contaminated soil or groundwater. If there is contamination at a site it will need to be evaluated and likely remediated. Conducting up-front due diligence can help identify some concerns so that facility designs and budgets can be adjusted to adequately address risks. Different regulatory agencies have different requirements for each potential contaminant type, making for a complex process if cleanup or remediation is required. Having an experienced environmental scientist familiar with local regulations is essential to help navigate the process.
If you’re preparing for a K-12 development project, we hope the suggestions above will be valuable. Proper planning and consultation with experts can prepare your project for success, and reduce the risk of costly project adjustments. If you have any questions, don’t hesitate to contact us for assistance.