By Keeli Parkey
Testing continues on the grounds of Love Chapel Elementary School, Director of Schools Denise Brown said during a regularly scheduled meeting of the Unicoi County Board of Education on Thursday, Sept. 14.
A sinkhole, which measured at 25-26 feet wide and 122 feet deep and was located approximately 20 feet from the school building, was discovered on Aug. 18, and prompted the school system to relocate all of Love Chapels students, faculty and staff to Unicoi County Intermediate School and Unicoi County Middle School.
Brown updated the board, as well as the teachers, administrators and citizens in attendance, on the status of the school property. Love Chapel will remain closed until the school system is certain the property is safe to reopen, Brown said.
Brown told the board she recently received a report from HSA Engineers & Scientists entitled, Report of Distress Evaluation and Geotechnical Assessment for Love Chapel. She presented copies of this report to the board and to local media outlets.
Regarding the emergency response to the sinkhole, the report states: There appeared no obvious predicating events that could have contributed to the formation of the depression; however, a significant rain event was reported in an area about one (1) week prior to the ground collapse. HSA was also made aware of a similar sized sinkhole feature on a neighboring property, about 250 +/- feet to the east-northeast.
The report also details the scope of services HSA has provided since it was sent to the property by the school systems insurance company.
The services include, according to the report: a site visit; the review of information regarding the makeup of the soil around Love Chapel and in the northeast Tennessee region; a multichannel analysis of surface waves which assessed the lateral/vertical continuity of soil strata; and a relative elevation floor survey to map the respective floor surface(s), and evaluated whether significant differential movement of this structure may have occurred based on the results.
Other services included the excavation of three test pits and the performance of five Standard Penetration Test borings using a truck-mounted drill rig.
Brown told the board the borings were anywhere from 60 feet to 120 feet deep. Soil samples were collected at five-foot intervals in these borings.
They did three (borings) really close to where were seeing the damage and the movement, close to the sinkhole, Brown also said. They did two a little further out to get a comparison of what type of soil youre looking at.
Brown said the tests performed by HSA for this report took place only near the northeast wing, which is the side of the school building where the sinkhole is located. This part of the school is an addition to the original building constructed in 1988.
Were still ongoing. There is still more testing going on, even today, she also said during Thursdays meeting. I expect to have people on site again next week. This is just dealing with this one particular area; the wing we added.
The report also includes photos of building distress in this wing.
Captions with the photos describe damage such as:
an approximately ½ inch wide walkway/wall expansion joint at the north side of building addition;
an approximately 3/8-1/2-inch wide crack in the concrete floor slab of classroom 103; and
a 3/8 inch wide crack in the masonary column of classroom 103.
Regarding damage to the interior of the building, the report also states: Significant commensurate damage was identified near the northeast corner of the building (classroom 103). Comparatively less severe damage was noted in the remaining building sections assessed as part of this study.
Regarding the floor surface topography of the building, the report states that a general downward trend towards the northeast was noted at the north end of the building.
The report then states: Considering the relatively significant commensurate distress near the northeast corner of classroom No. 103, it is our opinion that the topography of the north end of the building addition was reflective of differential movement of the structure.
Most of the damage we have is within that wing. Not only classroom 103 in that new wing we have cracking throughout those classrooms, some more severe than others, Brown told the board.
The HSA report also includes several pages of recommendations for the remediation of sinkhole activity, as well as localized foundation stabilization and cosmetic repairs.
Before discussing these recommendations Brown reiterated to the board and to the audience that the tests discussed in the HSA report she presented during the meeting were performed only in and around the northeast wing of the building, which was added to the original structure in 1988. The recommendations are based only on these tests.
I want to stress this point, especially to the media, this is a recommendation, this is not something that is going to happen because we are in the process of doing several more tests, Brown said. I just want to make sure that we get the information out there correct to the public. One thing that this board and I have tried to do from the very beginning is make sure we tell you everything we know, be very honest about it and answer your questions. I dont need any type of misunderstanding that this is what the school board is going to do because this is not where were at at this point.
… I want to emphasize that there is more testing going on. We had people on site today for eight-and-a-half hours, she continued.
Brown said that based only on the five borings in the area around the sinkhole, the water floor leveling test and the seismic testing in only this one area, HSA recommended injecting cementitious grout, under pressure, into the subsurface; and installing an estimated 25 exterior underpins and nine interior underpins.
The deeper sinkhole activity zones can be remediated by injecting a low to moderate slump (3 to 5 inch slump) cementitious grout, under pressure, into the subsurface, Brown read from the report. The purpose of the grout injection program is to grout within and along the top surface of the bedrock (where evident) that connect the soils that overlie the rock surface to suspected cavernous bedrock zones, thereby reducing the potential for future subsoil raveling and migration. In addition, the grouting may serve to compress and reinforce weak soil zones.
HSA also recommends, based on the tests performed in and around the 1988 wing addition, the installation of injection pipes.
They will have to do this at specific places that the engineers will identify at specific types of pressure, Brown said. HSA has recommended 32 grout injection pipes be installed.
Another recommendation, based on HSAs tests, is the installation of an estimated 25 exterior underpins and nine interior underpins using helical piers. These underpins are recommended because they will, according to the report, reestablish foundation support and to relevel the affected sections of the structure.
What they are saying and again we are doing more tests, this is not something were going to jump in and do if you did grouting, then after approximately 2-3 weeks with the grouting, they would come in and do the helical piers, the underpinning process; it has to be done and designed by a structural engineer and overseen by the HSA engineers, Brown said.
If these steps were taken, the next step, after the installation of the helical piers, would be a waiting period of 6-8 weeks before any cosmetic repairs could take place.
Brown told the board that at first, the insurance company only offered to perform the tests described in the HSA report. This, she said, was unacceptable and requested additional testing of the property and building beyond what had already taken place.
We have concerns throughout the building, Brown said during her presentation. We have observed some cracking in an area that is on the other side of the building from the wing. That raises a red flag for me. We observed some off the kitchen, some cracking off the gym We have forced them into doing more testing.
Testing was under way on Wednesday and Thursday, Brown said, and crews are expected to be on site this week to perform further drilling tests.
I think we are looking at a process of several months before we really know what we can do, Brown said.
Renea Jones-Rogers, board chairperson, asked Brown if all the tests, once complete, will provide the board with the information they will need to make a decision regarding the return of students and teachers to the school.
Yes, Brown said. When they finish then well have the information to make the decision we need to make.
Brown also told the board once testing is complete another set of recommendations will be sent to school system officials.
She also said that the Love Chapel school building is insured for an estimated $5 million. The school system has been reimbursed by its insurance company, Risk Management Trust, for the estimated $40,000 in costs it has incurred due to the sinkhole.
Board member Lisa White asked Love Chapel Principal Ben Evely how the students have adjusted to the move.
For the remainder of this article please pick up the Sept. 18 edition of the Erwin Record.