side of the main chapel. The baptistery and sacristy were featured along with two other chapels, making the church a family chapel. The church overall has a vaulted Gothic rib ceiling, making the interior volume large. The church does not have a central dome, making it unique. The materials used were mostly hard and resonant, from marble and Istrian stone tile floors, to masonry walls, and vaults with brick covered with intonaco. Bell tower structural intervention Following the collapse of St. Mark's bell tower, cracks started to form on the Frari bell tower in 1904. This led to a structural intervention at the Frari. An investigation of the Frari bell tower began in 1990. With structural problems identified in 2000, the tower was investigated deeply in 2001-2003 using a monitoring system to identify crack patterns. The stress was also measured using flat-jack testing. Overall, the tower was inspected geotecnically in great detail, including the use of standard penetration tests and digging through the bell tower foundation. A structural analysis of the bell tower was then performed, and the forces and loads needed to fix the tower were calculated. After the investigation, several instruments, including a crack-gauge and a strain gauge were used to keep track of the work on the bell tower in real time. Strengthening interventions were conducted to keep the tower safe and used with a structural-geotechnical monitoring system. The first phase involved using a steel cable connecting one of the columns to the bell tower of the Frari. The second phase involved injecting mortal into the soil so that the soil would be strengthened in order to accommodate the increased stress. The most information derived during the first phase came directly from the bell tower and the precision leveling. The mortar was grouted to determine the velocity of the different intervention phases. At the end, the settlement velocity decreased. The third and final phase of the intervention involved a structural joint between the tower and the church. Although it took six months to execute and resulted in extensive deformations in the tower, it was successful and has prevented damage to the bell tower and parts of the church. Overall, soil-fracture intervention and structural-joint execution both use the direct pendulum. The structural joint contributes to prevention of future cracks when seismic loads occur. Pipe organs History The first historical information about organs in the Frari basilica dates back