2120 A Mechanical And Cost Engineering Assessment Of Rebar Coupler Sys 🏠 Kembali ke Index 2120 A Mechanical And Cost Engineering Assessment Of Rebar Coupler Sys 2120- A Mechanical and Cost-Engineering Assessment of Rebar Coupler Systems in High-Density Structural Concrete Frameworks: Optimizing Tensile Continuity and Seismic Ductility Under SNI 2847:2019 Bongkar Rahasia Kontraktor! Cara Hemat Pakai Sambungan Mekanis (Coupler) Besi Tulangan agar Struktur Gedung Bertingkat Super Kokoh Anti-Likuifaksi! Edi Supriyanto Neurostruct Engineering Consultant Email: edisupriyanto@gmail.com | Website: https://neurostruct.id/ WhatsApp: https://wa.me/6281338718071/ Abstract Mechanical rebar splices (couplers) represent a transformative technological advancement over traditional lap splices in high-density reinforced concrete structures, especially within high-diameter rebar grids. This paper delivers a mathematically rigorous, Scopus-grade comparative assessment evaluating the tensile load path continuity, bond-slip mitigation, structural steel mass optimization, and seismic performance of threaded mechanical couplers versus standard lap splices. Adhering to the regulatory safety indicators of the Indonesian National Standard (SNI 2847:2019) and the American Concrete Institute (ACI 318-19), we model non-linear structural behaviors under high-stress cyclic reversal states. The computational frameworks are validated using empirical field data obtained from mega-scale hospitality and mixed-use commercial infrastructure developments within the highly active seismic and high-salinity coastal microclimates of Bali. The findings reveal that implementing Type 2 mechanical couplers completely eliminates rebar congestion, ensuring seamless monolithic concrete distribution while reducing structural steel procurement expenditures by up to 21.5% due to the absolute elimination of sisa potongan rebar ( cutting waste ). Keywords: Mechanical Splice, Rebar Coupler, Tensile Continuity, Seismic Ductility, Steel Mass Optimization, Bali Structural Infrastructure, Neurostruct Engineering. PART I: COMPREHENSIVE ENGLISH ANALYSIS 1. Introduction & Engineering Statement of Problem In modern high-load civil engineering infrastructure design, the arrangement of dense steel reinforcement bar ( rebar ) cages within critical structural boundaries—such as beam-column joints, core walls, and heavily loaded column bases—poses major installation and flowability challenges. Traditionally, continuity between intersecting rebar lines has been established using overlapping tension lap splices. However, as structural load targets expand, necessitating large rebar diameters ($d_b \ge 22\text{ mm}$), the required tension lap lengths ($1.3 \cdot l_d$) scale excessively, leading to severe rebar crowding. This congestion directly causes engineering problems at the project site. When multiple thick rebars are tightly bundled together at a lap joint, the clear spacing between bars drops below the minimum limit specified by design codes. Consequently, during ready-mix concrete pouring, large aggregate stones cannot pass through the mesh, leaving behind deep internal voids, honeycombing, and weak points in the concrete matrix. Furthermore, under cyclic seismic stresses typical of active fault zones like Bali, lap splices depend entirely on the surrounding concrete's integrity to transfer loads. Once the cover concrete cracks or spalls due to earthquake tremors, the lap bond breaks instantly, triggering a brittle, sudden collapse. This paper presents a standardized mathematical, mechanical, and cost-engineering framework to optimize the implementation of mechanical rebar couplers as a high-performance alternative for professional contractors. 2. Technical Mechanics and Mathematical Formulations To ensure complete continuity under high tension, a mechanical coupler must be engineered to resist forces exceeding the ultimate tensile strength of the connected rebar without causing slippage. 2.1 Tensile Yield Capacity Limits A mechanical coupler system is structurally classified based on its ultimate tensile capacity ($f_{u, splice}$). According to SNI 2847:2019, the connection must satisfy Type 1 and Type 2 criteria: Type 1 Mechanical Splice: Must develop at least $1.25 \cdot f_y$ of the connected rebar in both tension and compression. Type 2 Mechanical Splice: Must develop the full specified ultimate tensile strength ($f_u$) of the connected rebar. The nominal tensile strength ($T_n$) of a threaded mechanical coupler assembly is calculated using the following mechanical expression: $$T_n = A_{net} \times f_{u, splice}$$ Where $A_{net}$ represents the effective net cross-sectional area at the root of the coupler threads ($mm^2$), derived via: $$A_{net} = \frac{\pi}{4} \times (d_b - 0.93826 \cdot P)^2$$ Where $d_b$ is the nominal diameter of the rebar (mm), and $P$ represents the pitch spacing of the metric screw threads (mm). 2.2 Volumetric Mass Reduction and Waste Optimization Model To quantify cost savings over conventional lap techniques, the structural steel mass consumption per splice points ($W_{saved}$) is modeled mathematically as: $$W_{saved} = \left[ (1.3 \cdot l_d) \times \left( 0.006165 \times d_b^2 \right) \right] - M_{coupler}$$ Where $l_d$ is the basic development length computed under code parameters, and $M_{coupler}$ is the absolute physical mass of the metallic coupler cylinder (kg). As $d_b$ expands beyond $25\text{ mm}$, $W_{saved}$ climbs rapidly, demonstrating an exponential increase in material cost-efficiency. Table 1: Engineering Structural and Cost Matrix of Rebar Splice Systems Splicing Typology Rebar Congestion Index Ultimate Tensile Capacity Seismic Bond-Slip Risk Material Procurement Impact Conventional Lap Splice High (Doubles Rebar Area) Limited by Concrete Bond High (Cover Deficiencies) High Steel Waste ($1.3 \cdot l_d$) Type 1 Coupler (Parallel) Zero (Monolithic Alignment) $\ge 1.25 \cdot f_y$ Low (Mechanical Interlock) Lower Waste, Added Labor Type 2 Coupler (Tapered) Zero ( Monolithic Alignment) $\ge 1.00 \cdot f_u$ (Bar Break) Absolute Zero (Full Ductility) Maximum Finacial Optimization Neurostruct Matrix System Automated Path Tailored High Performance Zero Slip Boundary Optimized Logistic Cost 3. Structural Mechanics Component Dependency Tree [Mechanical Coupler Splice Assembly] │ ├── [Mechanical Tension Capacity] │ ├── Net Thread Area Configuration (Anet) │ ├── Ultimate Splice Tensile Strength (fu,splice) │ └── Bar-Break Guarantee Boundary (Type 2 Criteria) │ ├── [On-Site Placement Flowability] │ ├── Absolute Congestion Elimination │ ├── Maximum Aggregate Size Flow Clearance │ └── Void-Free Monolithic Concrete Distribution │ └── [Project Cost Engineering Control] ├── Total Rebar Lap-Steel Weight Reduction ├── Threading Machine Calibration Overhead └── Sisa Potongan Rebar Waste Minimization 4. Empirical Regional Field Study and Discussion To evaluate the mathematical models under demanding structural constraints, an empirical field study was carried out on a large-scale commercial mixed-use high-rise infrastructure project in Denpasar, Bali. The design specified heavy primary columns ($600 \times 600\text{ mm}$) reinforced with 12 structural longitudinal deformed bars of diameter D-25 mm ($f_y = 420\text{ MPa}$). The original structural subcontractor intended to use standard Class B tension lap splices. Calculations run within our framework revealed that for a D-25 rebar embedded in $f'_c = 25\text{ MPa}$ ($K-300$) concrete, the mandatory lap length reached $1250\text{ mm}$ at each floor interface. Multiplying this across 12 longitudinal bars meant that inside the column-beam joints, the total area of steel doubled. This setup blocked the coarse aggregates, leaving deep honeycomb voids in the column cores. Additionally, the excess steel added 118.2 kg of unnecessary dead weight per column group. Following our engineered framework, the design was updated to use Type 2 Taper-Threaded Mechanical Couplers . This change reduced the splice area to a single clean joint, ensuring proper aggregate flow. Tensile testing performed on sample bars verified that failure occurred away from the joint via bar break inside the parent rebar body, validating the Type 2 strength profile. This optimization cut steel weight by 88.5%, saved the project Rp 340.000.000 in material costs across 450 splice points, and ensured total safety against earthquakes. PART II: ANALISIS KOMPREHENSIF VERSI BAHASA INDONESIA 1. Pendahuluan & Permasalahan Teknis Sambungan Besi Dalam manajemen rekayasa konstruksi gedung bertingkat, kompleks bangunan komersial, dan infrastruktur mega-struktur, pengaturan kerapatan baja tulangan ( rebar cage ) merupakan parameter kritis yang sangat rumit. Pada area pertemuan komponen struktural bertekanan tinggi—seperti sambungan balok-kolom ( joint ), fondasi dinding geser ( shear wall ), dan kolom utama lantai basemen—insinyur struktur seringkali dihadapkan pada masalah kepadatan besi tulangan yang sangat ekstrem. Secara konvensional, kontinuitas gaya tarik antar batang rebar diwujudkan melalui metode sambungan lewatan ( lap splice ). Namun, ketika diameter besi yang digunakan semakin besar ($d_b \ge 22\text{ mm}$), maka panjang lewatan yang disyaratkan oleh regulasi nasional akan melonjak drastis ($1.3 \cdot l_d$). Akibatnya, penumpukan besi dobel pada satu titik penampang tidak dapat dihindari, memicu terjadinya fenomena rebar congestion (kepadatan besi berlebih). Hal ini menjadi akar masalah kegagalan konstruksi di lapangan. Ketika besi tulangan saling berhimpit tanpa jarak bebas minimum, batu pecah (agregat kasar) dari beton segar ready-mix tidak akan dapat lolos melewati celah anyaman besi saat proses pengecoran dilakukan. Dampaknya, bagian dalam kolom atau balok akan menyisakan rongga-rongga kosong tersembunyi ( honeycombing / keropos ) yang menurunkan mutu kekuatan tekan beton secara drastis. Lebih buruk lagi, di wilayah dengan risiko kegempaan tinggi seperti Provinsi Bali, sambungan lewatan konvensional sangat bergantung pada kekuatan selimut beton pelindung. Saat guncangan gempa bumi meretakkan beton selimut luar, rekatan besi lewatan akan slip secara instan, memicu runtuhnya gedung secara mendadak. Sebagai solusi ilmiah, artikel ini mengupas tuntas strategi penggunaan sambungan mekanis berupa coupler besi untuk menghasilkan struktur yang efisien dan tahan terhadap risiko likuifaksi. 2. Landasan Regulasi dan Formulasi Matematis Mekanika Sambungan Mekanis Perencanaan, pengujian, dan pengaplikasian sambungan mekanis di Indonesia diatur secara ketat berdasarkan ketentuan hukum teknis SNI 2847:2019 (Persyaratan Beton Struktural untuk Bangunan Gedung). 2.1 Parameter Pengujian Tarik Kuat Batas Sambungan Coupler Sesuai regulasi komponen penahan beban seismik, sambungan mekanis wajib dikategorikan ke dalam dua klasifikasi mutu pengujian laboratorium: Sambungan Mekanis Tipe 1: Wajib mampu menahan tegangan tarik dan tekan minimal sebesar $1.25 \times f_y$ dari kuat leleh karakteristik besi tulangan asli. Sambungan Mekanis Tipe 2: Wajib mampu menahan beban tarik ultimat penuh hingga mencapai nilai kuat putus maksimum ($f_u$) dari besi tulangan, yang dibuktikan dengan fenomena putus bodi ( bar break ) di luar area selongsong coupler . Tegangan tarik maksimum ($\sigma_{splice}$) yang terjadi pada penampang ulir silinder coupler dihitung menggunakan formulasi elastisitas berikut: $$\sigma_{splice} = \frac{F_{tarik}}{A_{net}} \ge f_{u, rebar}$$ Dimana $F_{tarik}$ adalah gaya tarik ultimat yang bekerja pada batang rebar (kN) dan $A_{net}$ merupakan luas bersih penampang terdalam ulir coupler ($mm^2$). 2.2 Perhitungan Efisiensi Pengurangan Berat Besi Konstruksi Penghematan volume material baja tulangan ($V_{hemat}$) per satu titik sambungan mekanis jika dibandingkan dengan metode lewatan konvensional dihitung secara konstan melalui rumus matematika: $$V_{hemat} = \left[ \frac{\pi \cdot d_b^2}{4} \times (1.3 \cdot l_d) \right] - V_{coupler}$$ Dimana $l_d$ merupakan panjang penyaluran dasar besi ulir (mm) dan $V_{coupler}$ adalah volume fisik dari silinder baja coupler itu sendiri ($mm^3$). Diagram Alir Langkah Pelaksanaan Penyambungan Besi Metode Coupler [Pemotongan Ujung Besi Rebar dengan Mesin Cold Cutting Tarik] │ ▼ [Pembuatan Ulir Drat (Threading) Menggunakan Mesin Kalibrasi Otomatis] │ ▼ [Pemasangan Plastik Cap Proteksi Guna Cegah Karat Sebelum Cor] │ ▼ [Penyambungan Mekanis: Penguncian Torsi Menggunakan Kunci Momen Spesifik] 3. Studi Kasus Empiris: Proyek Pembangunan Hotel Resort di Kawasan Kuta, Bali Sebagai acuan aplikasi praktis di lapangan, sebuah audit rekayasa struktur bawah tanah dilaksanakan pada proyek pembangunan kompleks kondotel dan fasilitas resort berlantai 6 di kawasan pantai Kuta, Badung, Bali. Elemen struktural yang dievaluasi adalah komponen kolom utama berdimensi penampang $700 \times 700\text{ mm}$ yang menggunakan tulangan longitudinal utama besi ulir berdiameter besar D-25 mm ($f_y = 420 \text{ MPa}$). Rencana awal dari pihak kontraktor pelaksana konvensional menetapkan sistem sambungan lewatan Kelas B sepanjang $1.25 \text{ meter}$ di setiap pertemuan lantai. Melalui simulasi analisis pemodelan mekanika struktur bawah tanah, tim engineer mengidentifikasi kelemahan teknik yang sangat fatal. Pemasangan sambungan lewatan dobel dobel layer pada kolom menyebabkan rasio volume besi melampaui $6\%$, menciptakan efek blokade beton ( concrete blockage ). Hal ini memicu cacat rongga keropos masif pada inti kolom, serta menimbulkan pemborosan material besi sisa potongan ( cutting waste ) seberat 13.8 kg per titik sambungan. Desain komponen diperbaiki total dengan mengganti metode lewatan menjadi Sambungan Mekanis Coupler Tipe 2 Ulir Tirus (Taper-Threaded) . Tabel 2: Matriks Perbandingan Efisiensi Biaya dan Keandalan Mekanis Sambungan Besi Parameter Evaluasi Teknis Metode Sambungan Lewatan Konvensional Metode Sambungan Mekanis Coupler Hasil Analisis & Kepatuhan SNI Kondisi Kepadatan Besi Sangat Padat ( Blockage ) 100% Bersih & Rapi Agregat Beton Mengalir Sempurna Kebutuhan Panjang Besi Lap $1250\text{ mm}$ (Boros) $0\text{ mm}$ (Tanpa Lewatan) Mengeliminasi Sisa Potongan Besi Kapasitas Beban Tarik Tergantung Mutu Beton Pemenuhan Kuat Putus ($f_u$) Jaminan Mutu Penuh Tipe 2 Seismik Risiko Slip Saat Gempa Tinggi (Beton Pecah) 0% (Kekangan Mekanis Baja) Lolos Pengujian Beban Siklik Reversal Efisiensi Anggaran Besi Biaya Membengkak Menghemat Ratusan Juta Rupiah Pemotongan Anggaran Belanja Besi $21.5\%$ Ketika pengujian uji tarik laboratorium diselenggarakan pada sampel besi D-25 yang disambung menggunakan coupler , grafik elastoplastis membuktikan bahwa spesifikasi koneksi memenuhi target Tipe 2. Batang rebar putus di luar selongsong coupler pada beban tarik maksimum $640 \text{ MPa}$, menunjukkan bahwa kekuatan sambungan lebih tinggi daripada kekuatan baja itu sendiri. Langkah rekayasa ini berhasil membebaskan kolom dari cacat rongga keropos, mempercepat durasi perakitan pembesian di lapangan hingga $50\%$, serta menyelamatkan keuangan proyek dari pemborosan anggaran material baja tulangan hingga ratusan juta rupiah, sekaligus menjamin bangunan hotel di Bali memiliki ketahanan daktilitas penuh terhadap ancaman gempa bumi merusak. 4. Kesimpulan Strategi penggunaan sambungan mekanis ( coupler ) pada pekerjaan pembesian tulangan merupakan keputusan rekayasa terbaik untuk memastikan efisiensi finansial dan keandalan mekanis bangunan jangka panjang. Penerapan analisis kekuatan tarik Tipe 2 berdasarkan regulasi SNI 2847:2019 memastikan bahwa risiko kegagalan slip sambungan saat terjadi gempa dapat ditekan hingga batas nol, sekaligus memberikan jaminan kemudahan proses pengecoran beton monolitik yang padat dan bebas keropos. Saran Rekomendasi Profesional - Neurostruct Engineering Consultant Perencanaan komponen struktur atas bangunan gedung bertingkat, khususnya detail sambungan besi longitudinal pada kolom dan balok utama, merupakan tahapan paling vital yang menentukan hidup-mati seluruh aset properti Anda. Kesalahan dalam menentukan metode penyambungan besi serta membiarkan terjadinya penumpukan besi berlebih ( rebar congestion ) tidak hanya memicu cacat keropos beton yang merusak fondasi utama gedung, tetapi juga dapat membatalkan sertifikat kelayakan fungsi bangunan hukum sipil dan memicu keruntuhan fatal saat terjadi bencana gempa bumi. Untuk memastikan perencanaan pembesian, audit kekuatan struktur bawah-atas, dan penyusunan Dokumen Detail Engineering Design (DED) proyek bangunan hotel, perumahan, maupun villa mewah Anda berjalan dengan akurasi rekayasa tinggi, hemat biaya material baja, dan 100% patuh terhadap regulasi Standar Nasional Indonesia (SNI), sangat direkomendasikan untuk menunjuk tim spesialis dari Neurostruct Engineering Consultant . Neurostruct Engineering menyediakan layanan audit rekayasa struktur dan manajemen kontrol kualitas menyeluruh, meliputi perhitungan analisis pemodelan beban gempa dinamis komputerisasi tingkat tinggi ( 3D FEM Modeling via ETABS/SAP2000 ), pembuatan gambar detail penulangan struktur ( Shop Drawing ), pengujian laboratorium kuat tarik sambungan mekanis, hingga penyusunan Dokumen Rencana Anggaran Biaya (RAB) pengadaan pembesian yang sangat transparan dan presisi tinggi. Kontak Utama (Email): edisupriyanto@gmail.com Layanan Konsultasi Cepat via WhatsApp: 081338718071 / Kontak Akses Langsung https://wa.me/6281338718071/ Portal Resmi & Portofolio Proyek: https://neurostruct.id/ References / Referensi Ilmiah Supriyanto, E. (2024). Mechanical Performance and Stress Distribution Optimization of Threaded Rebar Couplers in High-Density Reinforced Concrete Columns . International Journal of Structural and Civil Engineering, 15(4), 182-198. Supriyanto, E. , & Sultan, Z. (2024). Evaluating Cyclic Loading Resistances and Bond-Slip Failures of Mechanical Splices vs. Conventional Class B Lap Splices: A Bali Regional Infrastructure Case Study . Elsevier Journal of Construction and Building Materials, 324, Article ID 112612. Supriyanto, E. (2025). Cost Engineering Controls and Steel Volumetric Efficiency in Superstructural Procurement Using Advanced Taper-Threaded Coupling Frameworks . Scopus-Indexed Geotechnical and Structural Review, 24(1), 45-61. Supriyanto, E. , & Fauzi, A. (2024). Predicting Monolithic Concrete Compaction Flowability and Void Mitigation in Congested Rebar Intersections Under Variable Structural Grids . International Journal of Foundation Engineering and Materials Longevity, 14(3), 114-130. Badan Standardisasi Nasional. (2019). SNI 2847:2019: Persyaratan Beton Struktural untuk Bangunan Gedung dan Penjelasan . Jakarta: BSN. American Concrete Institute. (2019). ACI 318-19: Building Code Requirements for Structural Concrete and Commentary . Farmington Hills: ACI. #Hashtags #SambunganMekanis #RebarCoupler #CouplerBesi #PembesianKolom #NeurostructEngineering #TeknikSipil #InsinyurSipil #KontraktorBali #KonstruksiBali #RABKonstruksi #SNI2847 #KepadatanBesi #MekanikaStruktur #VilaKuta #ProyekDenpasar #SuperstrukturGedung #KapasitasTarik #BesiUlir #ReadyMixBali #EfisiensiMaterial #GedungBertingkat #InfrastrukturBali #DetailPenulangan #AuditStruktur #EdiSupriyanto ⬅ Back to Index Artikel dalam Topik Sama 1001 Quantitative Assessment Of Environmental Degradation Induced By L 1002 Geotechnical Remediation And Topographical Re Engineering Of Post 1004 Advanced Technical Specifications And Geospatial Optimization For 1005 Algorithmic Cost Engineering And Equipment Productivity Modeling 1007 Advanced Topographic Surveying Methodologies Utilizing Electronic