Design of Deflection Measuring System for Steel Frame Bridge Structure
Yoga Alif Kurnia Utama*1
1Universitas Widya Kartika; Jl. Sutorejo Prima Utara II/1, Kota Surabaya, Jawa Timur
1Jurusan Teknik Elektro, Fakultas Teknik Universitas Widya Kartika, Surabaya e-mail: *1[email protected]
Abstrak
Berdasarkan data yang dihimpun dari BNPB, terbukti bahwa bencana yang terjadi di Indonesia pada periode 1 Januari hingga 5 Agustus 2021 yaitu sebanyak 1.677 bencana alam terjadi di Indonesia. Bencana tersebut antara lain banjir, tanah longsor, angin puting beliung, dan gempa bumi. Bencana alam ini memakan banyak korban dari bencana tersebut. Selain itu, bencana alam yang terjadi menghancurkan infrastruktur yang ada di daerah tersebut. Berbagai kerusakan infrastruktur telah melumpuhkan kehidupan warga di kawasan tersebut. Lebih parah lagi jika infrastruktur seperti jembatan rusak, hal ini dapat menyebabkan jalur akses transportasi akan terputus. Oleh karena itu pada penelitian ini akan dibuat suatu sistem untuk memeriksa kekuatan jembatan yang memiliki rangka baja. Pemeriksaan ini dilakukan dengan cara mengukur defleksi rangka jembatan, dan hasilnya lalu akan ditampilkan melalui LCD. Sistem ini mengukur defleksi rangka dengan memanfaatkan sensor strain gauge. Pengukuran ini akan dibandingkan dengan pengukuran menggunakan alat ukur defleksi aktual, LVDT. Hasil pengukuran menunjukkan bahwa sistem ini menghasilkan kesalahan pengukuran sebesar 3,79%.
Kesimpulannya, penelitian ini menunjukkan bahwa sistem ini cukup baik sebagai alat ukur untuk defleksi pada jembatan rangka baja truss.
Kata kunci: Arduino Uno, Jembatan Rangka Baja, LCD, Lendutan, , Strain Gauge.
Abstract
According to data compiled from BNPB, it can be seen that disasters occurred in Indonesia from the period of January 1 to August 5, 2021; as many as 1677 natural disasters occurred in Indonesia. These disasters include floods, landslides, tornadoes, and earthquakes.
These natural disasters took many victims of the disaster. In addition, the natural disasters that occurred destroyed the existing infrastructure in the area. Various damage to infrastructure has paralyzed the lives of residents in the area. This will be worse if the bridge is damaged because the transportation access point will be cut off. Therefore, this research will create a system to check the strength of a bridge that has a steel frame. This examination is carried out by measuring the deflection of the bridge frame, and the results are displayed through the LCD. This system measures a frame deflection by utilizing a strain gauge sensor. This measurement will be compared with measurements using the actual deflection measuring instrument, LVDT. The results show that this system's measurements produce a measurement error of 3.79%. In conclusion, this study shows that the system is quite good as a measuring instrument for deflection on a real steel truss bridge.
Keywords: Arduino Uno, LCD, Deflection, Steel Frame Bridge, Strain Gauge.
1. INTRODUCTION
The number of fatalities and property damage caused by natural disasters in Indonesia continues to rise with each passing year [1]. The national news windows on television often feature images of natural disasters from throughout the nation. Natural disasters are triggered by various factors, including the effects of climate change as well as environmental destruction [2].
When the rainy season in Indonesia begins, the water flow rate increases significantly. Because of this, the area may experience landslides or flooding [3].
On the other hand, the soil and vegetation will dry out if Indonesia experiences a dry season. A smog catastrophe was the inevitable outcome of this. The dry season is also a leading cause of drought as a natural disaster worldwide [4].The repercussions include water shortages and unproductive agricultural land that cannot be utilized to its full potential. Due to the fact that Indonesia is located in a mountainous region of the world, it is no longer possible to prevent earthquakes or volcanic eruptions in the region [5].
No matter the nature of the catastrophe, it is abundantly evident that the damages incurred as a result of a catastrophe are not insignificant. These losses include the devastation of infrastructure, including homes, schools, and other buildings. The bridge is frequently regarded as one of the most significant parts of physical infrastructure. The bridge connects one region to another and serves as a link between the two. The economy would reach a total standstill if roads were blocked off due to a damaged bridge[6]. Because of this, it is becoming increasingly challenging to evacuate those whom natural catastrophes have impacted. Because bridges play a vital role in connecting different areas, this study intends to create a system that can check the strength ability of a bridge.
This inspection will be carried out by measuring the deflection that occurs in each bridge frame. This is very important, especially in terms of strength (strength) [7] and stiffness (stiffness) [8], where the horizontal bar that is loaded laterally will experience deflection. The deflection that occurs in the elements subjected to loading must be at an allowable limit because if it exceeds the allowable limit, there will be damage to these elements or other elements.
For instance, on a transmission shaft, if the deflection is large enough, it will result in a greater vibration amplitude up until resonance occurs. This will continue to be the case until the shaft is in resonance. Because of this, the transmission system produces harsh sounds and vibrations and may even sustain damage to the shaft itself. In addition to this, it has the potential to accelerate the wear on the bearing that is located on the side of the shaft that is supporting it, as well as cause damage to the gear.
Based on economic considerations, properties, and strength, steel is a type of building material that is suitable for bearing loads. Therefore, steel is widely used as a structural material, for example, for the main frame of high-rise buildings as columns and beams, roof support systems with long spans such as sports buildings, hangars, antenna towers, bridges, earth retainers, pile foundations, harbor buildings, reinforcement walls in coastal reclamation, oil tanks, oil, water, or gas distribution pipelines.
2. METHODOLOGY 2.1 Literature Review
Two main components in the system will be made in this research, namely, Arduino Uno and Strain Gauge Sensor.
2.1.1 Arduino UNO
Powered entirely by the ATmega328, the Arduino UNO is a microcontroller board [9][10].The Arduino UNO features fourteen digital input or output pins (six of those that can be utilized as PWM outputs), an ICSP header, six analog inputs, a power connector, a sixteen MHz crystal oscillator, a reset button, and a USB port, as illustrated in Figure 1 below.The
microcontroller's support infrastructure is included with the Arduino UNO. With a USB cable, an AC to DC converter, or a battery, you may quickly get it started by connecting it to a computer.
Figure 1. Arduino Uno
Figure 2 depicts a simplified layout of the Arduino board. To expand the ability of the Arduino board, a shield may be mounted on top of the Arduino board. Instead of being a very complex assembly language, the programming language used by Arduino is more like or akin to the C++ programming language which can be made simpler with the assistance of Arduino libraries.
Figure 2. Arduino Uno Schematic Diagram
The technical data specifications contained on the Arduino UNO R3 board are as follows:
▪ Microcontroller : ATmega328
▪ Operating Voltage : 5V
▪ Input Voltage (recommended) : 7 - 12 V
▪ Input Voltage (limit) : 6-20 V
▪ Digital I/O pins :14 (6 of them PWM pins)
▪ Analog input pins :6 pin input 21
▪ DC current per I/O pin :40 mA
▪ DC current for pin 3.3 V :150 mA
▪ Flash Memory :32 KB with 0.5 KB used as the bootloader
▪ SRAM :2 KB
▪ EEPROM :1 KB
▪ Clock Speed :16 Mhz
2.1.2 Strain Gauge
A deformation or strain can be measured using an electrical component known as a strain gauge [11]. This instrument consists of a metal foil with insulating qualities that is attached to the research instrument which the pressure would be calculated, and the subsequent pressure is determined by loading. According to how it operates, when the item's pressure shifts, the metal wire would flex as well as the instrument's internal resistance would then shift.
A Wheatstone bridge is then utilized to feed the resistance value through the electrical circuit [12]. The Strain Gauge's level of resistance will then be identified. The strain gauge sensor is basically a metal wire type, where the grid configuration is formed through the photoetching process. Because the process is easy, it can be formed from various gauge sizes.
The smallest available strain gauge length is 0.20 mm, and the largest is 102 mm. Typical resistance strain gauges are 120 mm and 350 ohms. In addition, there are special purpose strain gauges available in 500, 1000, and 1000 ohms. (U.A. Bakshi, 2008). The image of the strain gauge is shown below
Figure 3. Strain Gauge Sensor 2.3 Research Method
The aims and purposes of hardware and software planning must be mutually supportive and related to achieving satisfactory results at the end of the conclusion. In system design, measurements and calculations are also carried out meticulously and thoroughly in order to reduce the risk of the system failing when it is put into use later.
Figure 4. Research Method Flowchart START
Literature Study
END
Hardware &
Software Design Hardware & Software
Implementation
Data Analysis Data Report
Success?
N
Y
The approach to the research that was taken may be broken down into several stages, all of which are detailed in the flow chart that can be found above in Figure 4. The system that will be made in this study refers to the block diagram in Figure 5 below
Figure 5. System Block Diagram
Figure 5 shows that this system comprises three main components: a strain gauge sensor, an Arduino UNO, and a 16x2 LCD. This strain gauge sensor will be attached to the rod whose deflection will be measured, then connect the sensor to the Arduino Uno.
Arduino is used to read the strain gauge sensor. If the measuring rod is deflected, the strain gauge will widen or shrink. Changes in the shape of this strain gauge will result in a change in resistance.
Before entering the Arduino Uno, the strain gauge sensor will be connected to a Wheatstone Bridge circuit so that this resistance change can be read by the Arduino Uno. Figure 6 shows the shape of this circuit and how it is connected to the strain gauge sensor.
Figure 6. Wheatstone Bridge
With a Wheatstone bridge circuit, the change in resistance in the strain gauge will turn into a change in voltage. The Arduino Uno will read this voltage change. This is because a microcontroller cannot measure resistance if it has not been converted into voltage. The ADC Pin (Analog Digital Converter) will read this voltage value.
From this pin, the voltage value can be converted into a deflection value. Then the value of this deflection will be further displayed through the 16x2 LCD. After the system has been made, the next step is to take 25 deflection data which will then be compared with the actual deflection measurement tool, LVDT.
The Linear Variable Differential Transformer (LVDT) sensor is usually used to measure or detect small movements to the most minor possible movement. In addition, the sensor has two secondary coil parts, namely the premier coil and a ferromagnetic material core. All coils have a coil in the pipe, while the core is located in the middle of the pipe. The physical form of LVDT can be seen in Figure 7. below.
Arduino Uno Strain Gauge
LCD 16x2
Figure 7. LVDT
The advantages of this sensor, when compared to other sensors, are as follows:
▪ Does not cause friction
The sensor has an advantage in the feature that it is friction-free or does not cause friction.
This feature is made so that the sensor can keep the core part of the LVDT touch so that friction does not occur. This feature is one of the advantages of the sensor.
▪ Dynamic and have a fast response
Since there won't be any friction when the sensor is in use. It may react rapidly to something because of the sensor.
▪ Have an unlimited resolution
Although LVDT sensors have an infinite resolution, the screen resolution and signal distortion in the conditioner signal limit their use.
▪ Sensor results can be safer
The data that the sensor has collected will not be lost if it unexpectedly loses power while it is operating and it might even be recovered
3. RESULTS AND DISCUSSIONS .
3.1 Hardware Design
As previously demonstrated, this research will produce a system that can measure the deflection of a frame. In measuring the results of the system that has been made, this system will measure the deflection.
At the same time, it will be compared with the results of measurements that have been made by using LVDT. Both values will be stored in table 1. After that, the measurement error that emerges in each data will be calculated using the formula below.
%𝐸𝑟𝑜𝑟 = |𝑑𝑠𝑒𝑛𝑠𝑜𝑟− 𝑑𝑙𝑣𝑑𝑡
𝑑𝑙𝑣𝑑𝑡 | . 100%
Which:
% Error = Percentage Error
dsensor = Deflection measured deflection from the system dlvdt = Deflection measured from LVDT
The tests that have been carried out can be seen in Table 1 below.
Table 1. Hardware Testing
No dsensor(mm) dlvdt(mm) Error (%)
1 0.3 0.38 21.05
2 0.7 0.78 10.26
3 1.4 1.53 8.50
4 1.9 2.05 7.32
5 2.4 2.52 4.76
6 2.8 2.95 5.08
7 3.1 3.22 3.73
8 3.4 3.28 3.66
9 3.9 3.8 2.63
10 4.3 4.45 3.37
11 4.7 4.89 3.89
12 5.1 4.98 2.41
13 5.5 5.39 2.04
14 5.8 5.87 1.19
15 6.3 6.44 2.17
16 6.7 6.78 1.18
17 7.1 7.28 2.47
18 7.5 7.65 1.96
19 7.9 7.98 1.00
20 8.4 8.3 1.20
21 8.9 8.84 0.68
22 9.2 9.11 0.99
23 9.6 9.52 0.84
24 9.9 9.75 1.54
25 10.4 10.31 0.87
Average 3.79
This test is done by taking data 25 times. After that, the average measurement error will be taken. The results above show that the average error or measurement error that occurs is 3.79%.
This is good enough to be used as a measuring tool that is quite precise.
4. CONCLUSION
This research makes a system that can measure the deflection for a bridge frame. This system utilizes a strain gauge sensor that will measure the deflection, which will be compared with the LVDT deflection gauge. The results show that from the 25 measurement data, it was found that the average measurement error that occurred in the system made in this study is 3.79%.
This value indicates that this system is good enough to be a tool for measuring the deflection of a steel frame.
REFERENCES
[1] Maryanti, S, Saputra, A., 2019, Analisis Kerusakan Bangunan Fasilitas Sosial Akibat Gempabumi Tahun 2018 Di Kota Palu Provinsi Sulawesi Tengah, Prosiding Seminar Nasional Geografi, Palu, 28 September
[2] Azizah, M., et al., 2022, Pengaruh Perubahan Iklim Terhadap Bencana Hidrometeorologidi Kecamatan Cisarua-Kabupaten Bogor, Jurnal of Science Education, vol 1, no 2, hal 541-546 [3] Eldi, 2020, Analisis Banjir di DKI Jakarta, Jurnal Inovasi Penelitian, vol 1, no 6, hal 1057-
1064.
[4] Haji, A.T.S., Wirosoedarmo, R., Ariyani, I., 2016, Analisis Pola Perubahan Tingkat Kekeringan Kabupaten Bojonegoro Berdasarkan Theory Of Run, Jurnal Sumberdaya Alam dan Lingkungan, vol 3, no 1, hal 20-27.
[5] Syafitri, Y., Bachtiar, Didik, L.A., 2018, Analisis Pergeseran Lempeng Bumi Yang Meningkatkan Potensi Terjadinya Gempa Bumi di Pulau Lombok, Jurnal Fisika dan Pendidikan Fisika, vol 4, no 2, hal 139-146
[6] Qomaruddin, M., 2015, Analisa Kerusakan Jembatan Bongpes Desa Gerdu Kabupaten Jepara, Jurnal Disprotek, vol 6, no 2, hal 77-81
[7] Harsoyo, Y.A., et al., 2021, Beban Maksimum, Tegangan, Lendutan Dan Momen Curvatur Pada Variasi Jembatan Beton Balok T Dengan Menggunakan Software Response 2000, Jurnal Konstruksia, vol 13, no 1, hal 113-127.
[8] Setiati, N.R., 2015, KEKUATAN STRUKTUR JEMBATAN GANTUNG SEDERHANA UNTUK PEJALAN KAKI, Jurnal HPJI, vol 1, no 2, hal 67-76
[9] Muhajir, A., 2020. Rancangan Sistem Sensor Pengukur Suhu Berbasis Mikrokontroler Arduino Uno Dengan Sensor DS18B20. Program Sarjana Teknik Nuklir dan Teknik Fisika.
Universitas Gadjah Mada, Yogyakarta.
[10] Utama, Y.A.K., et al., 2019, Perbandingan Kualitas Antar Sensor Kelembapan Udara dengan Menggunakan Arduino Uno, Prosiding Seminar Nasional Sains, dan Teknologi, Semarang, 31 Juli
[11] Saputra, H., Yusfi, M., 2013, Rancang Bangun Alat Ukur Regangan Menggunakan Sensor Strain Gauge Berbasis Mikrokontroler ATMEGA8535 Dengan Tampilan LCD, Jurnal Fisika Unand, vol 2, no 3, hal 162-169
[12] Simanjuntak, I.U.V., et al., 2021, Penggunaan Strain Gauge Sebagai Kendali Kursi Roda, Jurnal Ilmiah Teknologi dan Rekayasa, vol 26, no 2, hal 154-169
