Leading Thoughts: 4/17/19 Why Tight Urban Sites Require More Ground Improvement Planning

Charles Allgood, P.E., talks about the common hassles that construction project managers run into when planning for ground improvement in urban areas with tight sites and busy roads. Be aware and plan ahead.   

Many people are returning to city life to avoid long commutes and gain more leisure time. As a result, cities are enjoying downtown and neighborhood revitalization.

Construction project management in an urban environment is a bit different from suburban or rural construction sites. You have busy and often narrow streets, tight property lines and close neighbors, to name a few. With those challenges in mind, here are common issues to consider if your urban project also includes ground improvement. We hope these thoughts will help you plan ahead and stay on schedule.

Street Navigation

Large, wide-load equipment, including the equipment used for ground improvement, can be moved in during periods of lower traffic. You will need flag people for traffic control and to help drivers navigate tight corners and site entry points — avoiding damage to overhead utilities, nearby buildings or any unplanned obstacles. Work with the city to ban street parking and thru-traffic on affected streets. Communicate with people in neighboring buildings about alternative parking and access points.

Nearby Buildings

With zero lot line construction a common occurrence, there are frequently nearby structures to consider., some with historical significance. Others are old and in poor condition. Your geotechnical engineer will recommend a pre-construction survey to record the existing conditions and note such things as cracks or foundation subsidence.

The geotechnical engineer should be called upon to establish vibrations limits for construction including the ground improvement. Geopier® has a suite of ground improvement techniques and some of them create lower vibrations compared to traditional pile driving or other ground improvement methods.

A good example of a historic building next to our work site is the Modera Cap Hill project in Denver, Colorado.

Access to Work Areas

It’s one thing to get our equipment to the site, but it’s another to move into an excavation below street level. For projects with underground parking areas there is usually a 10 to 12-foot excavation to enter.  Aggregate and cement grout delivery also need a ramped entrance.

The ramp will need to be gently sloped; this is especially critical for high mast equipment. During the work the ramp will have to be removed to allow improvement of the soil or footing in that location, and then replaced to restore the access.

To help with the project schedule and logistics we have improved basement level footings working from the street level grade.  Before any excavation work!


Concerns about public safety increase at an urban construction site. After you block off nearby sidewalks, of course you’ll try to keep the area clear of onlookers. There are also challenges with the installation and design of sheeting and shoring systems. These systems must sometimes be designed so as not to impeded the ground improvement work.

For all of these reasons, collaboration between the construction project manager, the geotechnical engineer of record and your ground improvement team will promote site safety and a well-maintained site. Be aware and plan ahead.