Structure Design Evaluation of Muhammadiyah Banjarmasin University Convention Centre Building Due to Functional Change Based on SNI 03-2847-2019

The Muhammadiyah Banjarmasin University Convention Centre Building was originally built as a guesthouse, over time it changed its function to become a place for lecture activities. Therefore, an evaluation of the initial structural design is carried out on the reliability of the building structure as regulated in Government Regulations in Permen PU No. 25 of 2007 concerning Certificate of Building Functioning or SLF. The data used in this study are primary and secondary data, where primary data is in the form of field tests to determine the uniformity of concrete quality, namely the bounce test using the Hammer Test tool on the beams and columns of the 1st floor and 2nd floor as many as 10 points, while secondary data uses preliminary planning data. Modeling is done in 3D using SAP2000 software. The results of research on the value of uniformity of concrete quality show mixed results, this is due to several factors, one of which is different casting methods in the field. Meanwhile, from the results of the analysis of the service ability of the building structure, the value of the Ultimate Moment ( Mu ) and Ultimate Load ( Pu ) as well as the Maximum Ultimate Moment ( Mr ) and Maximum Ultimate Load ( Pr ) is still able to withstand the loads acting on the structure even though it has changed its function based on SNI 03-2847-2019.


INTRODUCTION
The change of building function is an activity to change the loading on an old building according to the loading function of the new building used so that in this case an analysis of the structural strength of the building is needed, if the beam and column structure carries a load that exceeds its ability or is not in accordance with planning, it will experience local buckling and result in cracks or fractures in the structure.Building conversion is carried out to meet the functional needs of infrastructure as long as the building is still efficient to withstand the working load rather than building a new building.Building conversion can be an appropriate alternative.According to Nurhaliza (2021), structural analysis is a science that serves to determine the effect of loads on physical structures and their components.The results of structural analysis are used to see the strength of structures that will or have been built.Nurhaliza, Nuklirullah, and Bahar (2021) conduct research with the title "Analysis of the structure of beams and floor plates due to the change of building function (case study: Rectorate Building, Jambi University)" resulting in loading that occurs on beams and floor plates due to the change of building function that occurs in the rectorate building of Jambi University that can withstand new loads as a library, with analysis using manual calculations and ETABS software.
Building has a very important function for human life, especially to carry out daily activities so that the building needs to be maintained so that the building is able to stand firmly for a long period of time.The Muhammadiyah Banjarmasin University Convention Centre building stands for about three years and has changed its function which was originally planned as a guesthouse on the first floor and a hall on the second floor that turned into a place of teaching and learning activities for students and staff of the Faculty of Engineering, University of Muhammadiyah Banjarmasin on the first floor and remains a hall on the second floor.According to Musyafa (2018), building must include requirements; safety, health, comfort and ease.To fulfill the criteria in the https://journal.umy.ac.id/index.php/st/issue/view/1036building reliability rules, the government issued a regulation regarding the Certificate of Building Functioning or SLF.Therefore, this research was conducted to determine the service condition of the Muhammadiyah Banjarmasin University Convention Centre building due to changes in the function of the building with the title " Structure Design Evaluation of Muhammadiyah Banjarmasin University Convention Centre Building Due to Functional Change Based on SNI 03-2847-2019".

Location and Time of Research
This research In this research activity, a review of the dimensions of structural components was carried out directly in the field, taking several documents such as plan drawings and initial structural data and conducting rebound tests to determine the uniformity of concrete quality using hammer tests to obtain concrete quality at the Muhammadiyah Banjarmasin University Convention Centre Building, Main Campus of Muhammadiyah University Banjarmasin located on Jl.Gubernur Syarkawi, Handil Bakti, Kab.Barito Kuala, Provinsi.South Kalimantan.

Research Equipment
The equipment used to support the smooth implementation of research at the Muhammadiyah Banjarmasin University Convention Centre Building is as follows: Hammer test type HT225 is useful for testing concrete quality samples.Meter, used to measure the dimensions of the Muhammadiyah Banjarmasin University Convention Centre Building.

Methods
The research method used is the case study method (Evaluation).This method includes knowing the reactions that occur due to changes in the function of the building on the working load and can be done to analyse the strength of the building structure, especially on beams and columns in buildings that have been converted into lecture halls.The analysis process is in the form of remaking using the existing model in the initial plan drawing and conditions using SAP2000 student Version software.The stages in analysing the strength of the building structure consist of 4 stages which can be detailed as follows:

Data checking and collection stage
In the form of stages of collecting and checking data related to the implementation of research to analyse the structure of the Muhammadiyah Banjarmasin University Convention Centre Building that has changed its function.

Input Stage
This stage is a stage that explains the dimensions and specifications of structural elements, determining the working loads and 3D modelling using SAP2000 student Version Software.

Analysis Stage
The analysis stage is a continuation of the second stage carried out using SAP2000 student version software.Entering the calculation of forces in beam and column structural elements and combinations of working loadings.This analysis stage will get the Ultimate Load (Pu) and Ultimate Moment (Mu) values.

Output Stage
This last stage discusses the results of the forces in the structural elements that occur.At this stage the results of the analysis will be reviewed to see if it meets the requirements of the reduced nominal moment greater than the ultimate moment (Mr ≥ Mu) and nominal ultimate load greater than the ultimate ultimate load (Pr ≥ Pu).This review is used to see the strength of the structural elements in service condition for resisting the loading that works due to the change in building function.

Rebound Test Results using the Hammer Test
The hammer test was carried out on the columns and beams of the 1st floor, and the 2nd floor.The sampling points for the uniformity of concrete quality on the beams and columns of the 1st and 2nd floors of the Muhammadiyah Banjarmasin University Convention Centre Building can be seen in figure 1.In table 1, the test results of the uniformity value of the beam and column concrete quality on the 1st and 2nd floors of the Muhammadiyah Banjarmasin University Convention Centre Building get an average of 39.36 MPa so that it has reached the planning concrete quality value of 25 MPa, so in this research the modeling uses the planning concrete quality to calculate the safety factor.From the test results it can also be seen that the concrete quality obtained at several points is relatively different, the cause of the non-uniformity of the concrete quality is because the casting process in the field uses two methods, namely manually and using a concrete pump machine.

Loading Assignment
The loading data used for the calculation of the reliability of the Muhammadiyah Banjarmasin University Convention Centre Building which will be converted into a lecture hall for the Engineering Faculty of Muhammadiyah Banjarmasin University uses live loads based on the function of the building in accordance with SNI 1727-2020.The self-weight of the structure has been assumed in the SAP2000 student version software as self-weight.Additional dead load according to PPIUG 1983.Wind load calculation using SNI 03-1727-2013, the value of the wind load can be seen in Table 4 and Table 5.For earthquake loading using the RSA PSGeN website, DBTPP, Directorate General of Human Settlements, Ministry of PUPR to get the response spectrum in the Handil area with longitude (Longitude) 103.8749Degrees and Latitude (Latitude) -4.0549 Degrees is included in the SE -Soft Soil situ class, the spectrum response graph itself can be seen in Figure 3.The result of analyzing the strength of the column structure using SAP2000 student version software analyzing manual calculations according to SNI 2847-2019 obtained the results as in Table 6.Based on the analysis results in Table 6, the column element has met the design criteria for service condition on the maximum ultimate load value (Pr) exceeding the ultimate load (Pu).
From the results of analyzing the strength of the beam structure using SAP2000 student version software and analyzing manual calculations according to SNI 2847-2019, the results are shown in Table 7.
Based on the analysis results in Table 7, the beam element has met the design criteria for service condition, based on the value of the maximum ultimate moment (Mr) greater than the ultimate moment (Mu).

Figure 1 .Figure 2 .
Figure 1.Plan for taking the uniformity of concrete quality in beams and columns on Floor 1 of the UMBCC building

Table 1 .
Hammer Test Results

Table 3 .
Additional Dead Load

Table 4 .
Wind load away

Table 6 .
Results of Column Structure Analysis Pu ≤ Pr field area