3800 RIVERFRONT BLVD Geotech Report 2023-05-04

March 26, 2019 HWA Project No. 2015-061-21 Task 600-7 4.3.2 Anticipated Settlement Magnitudes along Riverfront Boulevard Long-term settlement magnitudes were estimated at 100-foot spacing along the proposed alignment of Riverfront Boulevard. Our analysis indicates that total settlement magnitudes, over a design life of 50 years, range from 9-inches to 30-inches along the roadway. The trend of anticipated settlement along the roadway alignment is shown in Figure 5 for 10, 20, 30, 40 and 50 years after completion of roadway construction. It should be noted that the settlement magnitudes shown in Figure 5 are approximate and could vary significantly based on conditions and composition of the refuse. As shown in Figure 5, we expect that the settlement along the roadway to be differential and result in several sags in the roadway profile over time. 4.3.3 Results of Anticipated Settlements The differential nature of the anticipated settlements along the roadway will affect several aspects of the roadway design and future maintenance cycles. As shown in Figure 5, the differential nature of the anticipated settlements along Riverfront Boulevard is expected to result in the development of several sags along the roadway. Over time we expect these sags to be visually noticeable and result in premature pavement distress. As a result, an increased pavement maintenance program should be anticipated. Asphalt pavement is recommended for the roadway due to its flexibility and relative ease of maintenance. The roadway is to be grade supported and is expected to settle over time, generally as shown in Figure 5. The adjacent building and portions of the frontage sidewalks are to be pile supported so that they do not settle over time. Therefore, large differential settlements are expected to occur over short distances between the proposed pile supported buildings and the adjacent roadway. The transition between these two elements should be designed to allow for periodic regrading between the road and the pile supported structures. The differential nature of the anticipated settlement along the roadway alignment is expected to affect proposed utilities constructed within roadway right of way. We recommend that all subsurface utilities be constructed using fused HDPE piping to provide maximum flexibility. More detailed utility recommendations are provided in Section 4.7. It is our understanding that some driveway access points, between pile supported buildings, are proposed along Riverfront Boulevard. If these driveway access points are to be pile supported along with the adjacent buildings, hinge slabs will need to be constructed to allow for a gradual transition between grade supported roadway and potential pile supported driveways. The length of the hinge slabs should be determined based on a maximum of 30 inches of settlement and the ' desired slope. 4.4 UTILITIES We expect that the Riverfront development will require the construction of numerous subsurface utility systems. We expect that many of these utilities will be constructed within the Riverfront Geotechnical Report Revision 3 26 2019.doc 13 HWA GEOSCIENCES INC.