Remediation of a building settlement caused by wetting of a foundation loess soil

A massive masonry Vukovar high-school building, built in 1894, is situated on a loess elevated terrain, supported partially with old masonry walls and partially with new concreate gravity retaining walls. During 1990's war it has been totally devastated. Several years after restoration, cracking on walls and signs of foundation settlements started to appear. There were two reasons of settlements: collapse of loess soil due to increased water content, and vertical movement of the soil in the vicinity of old tunnels in the foot of the hill. In 2008 a remediation of foundation soil under the part of the building with largest settlements was made by jet grouting. Observations on the building and surroundings performed afterwards indicated that settlements have stopped or significantly decreased in rate. At that time no other recommended remediation measures regarding the building and terrain around it were executed. Uncompleted remediation has left the possibility for additional settlements, therefore final investigation of foundation soil and structural elements of the building was planned in 2017. As additional and possibly final remediation measures, new remediation works on foundation and structural elements were designed in 2018. Main characteristics of previous activities and new design solution regarding the foundation improvement are presented in the paper.