Design of E.R. Building At Ct Arsa Palu Hospital With Liquefaction Potential

: This design hospital building is planned to be built in the city of Palu. Palu City has high earthquake potential, has history of liquefaction, tsunami and landslides disasters. Thorough design is needed so that this hospital building still become a place for health services after a disaster occurs. The building was designed using the Special Moment Resisting Frame Structure system based on the SNI. Earthquake load analysis uses the response spectrum method based on Earthquake Resistance Planning Procedures (SNI 1726:2019). This concept obtains structure design that meets SNI and still strong in strong earthquake and liquefaction. Analysis has been carried out and it was found that the potential for liquefaction to occur at a depth of 1.5 M to 4.5 M so that the foundation chosen was 4 piles with a diameter of 40 cm, a depth of 6 meters per pile cap. From the results of calculations, it shows that the structure of the emergency room building at CT Arsa Palu Hospital is safe from an analytical perspective .


METHOD
This structure was obtained from multi-level research on concrete, loading, earthquakes and liquefaction.Preceded by a literature study on concrete, loads, earthquakes and liquefaction.Next, preliminary design and structural modelling is carried out, including load modelling.Then a structural analysis was carried out with the help of SAP2000 and the FEM support program (Eka Wati & Ghozi, 2023).After all elements are safe and in accordance with SNI, then proceed with planning the foundation by considering soil conditions/lab results, column reactions and regulations.All research stages are simplified as seen in Figure 2.  The dimension of element for preliminary design is displayed in Fig. 3.

Concrete beam design
Moment and shear as result of structural analysis the displayed in Fig. 5 and Fig. 6.

Liquefaction potential
The liquefaction is already analyzed bay many researches (Allafa & Prasetya, 2019).The use of battered piles and prestressed concrete piles is not recommended on soils with high liquefaction potential (Badan Standardisasi Nasional, 2017), 12.2.4.3Effects of liquefaction on foundation design).Liqit software is then deployed to obtain potential liquefaction in this research.Boring and SPT log as data used in Liqit software is displayed in Fig. 10.And also the result of potential liquefaction is the displayed in Fig 11.It can be concluded that liquefaction in CT Arsa Palu Hospital area (which had safety factor <1) has the potential to occur at a depth of 1.5m to 4.5m and horizontal slide 80cm which equal to 80ton force.This horizontal force can only resisted by concrete pile, not wood pile.So the concrete pile foundation base must be at a level below 4.5 meters.

Foundation and Pile Cap
Load combination consider working load (DL x 1 + LL x 1 + earthquake x 1), and also two maximum conditions (DCon 2 and DCon 7), with Axial load 182525 kG, Moment 1527000kg-cm.So it required 4 D 40 cm pile, with reinforcement D22-150mm.Because liquefaction potentially occur at depth 4.5 M so it decided that the depth of concrete pile is 6 meters.Detail of pile cap and pile is displayed as seen in Fig. 12.

CONCLUSION
Research has been carried out to plan the structure and foundation of the ER building at CT Arsa Palu Hospital, namely 50/50 columns on the 1st floor, 40/40 columns on the 2nd and 3rd floors, 35/60 main beams and 25/40 child beams.The danger of liquefaction has been analyzed and it was found that the potential for liquefaction to occur at a depth of 1.5 M to 4.5 M so that the foundation chosen was 4 D 40cm piles in 6 meters depth per pile cap.The pile cap obtained is 200x200x60cm in size.Overall, the dimensions of the structure are safe according to SNI 1726-2012, SNI 2847:2019, SNI 1727:2020and SNI 8460:2017.

Figure
Figure 2. Research Flowchart

Figure
Figure 4. Spectrum Respond design and MCEG Map

Figure 7 .
Figure 7. Detail of beam reinforcement

Figure 12 .
Figure 12.Detail of Pile Cap