Capacity Of Connections Research Articles

Pull-out failure capacities of cold-formed steel batten screw connections at sub-zero temperatures

Cold-formed steel (CFS) roof and wall cladding systems are used worldwide, and are constructed using high-strength, thin steel battens and claddings. In North American countries, which are frequently subjected to blizzards (winter storms), these cladding systems are particularly vulnerable to pull-out failures during combined windstorm and snowy conditions. Despite extensive research studies investigating the pull-out failure mechanism and the critical parameters of screw connections between cladding and battens at ambient temperature, the behaviour of these connections under blizzard conditions has not been experimentally investigated. To fill this knowledge gap, an experimental study was undertaken that included 144 laboratory tests of screw connections in battens of varying grades and thicknesses, and three distinct types of screws. The pull-out failure capacities of screw connections in battens were evaluated under wind suction loading at four different temperatures, including ambient and sub-zero temperatures. The results of the study provided insights into the pull-out failure mechanisms of screw connections in battens and enabled the development of suitable design rules for combined wind action and sub-zero temperature conditions. The findings of this study are expected to be of significant value to engineers and building designers who are involved in the construction of lightweight cold-formed steel buildings.

Evaluation of dowel bearing strength of fungal-decayed cross-laminated timber

ABSTRACT Dowel bearing strength of three cross-laminated timber (CLT) species (Douglas-fir, Norway spruce, spruce pine fir) were periodically assessed through 40 weeks of exposure to two brown rot fungi species (Gloeophyllum trabeum and Rhodonia placenta). Time-dependent regression models were developed to describe the relationship between level of fungal exposure and dowel bearing strength of CLT. Obtained dowel bearing strength values were used to predict the capacity of floor-to-wall CLT connection systems. Predicted strength values were compared with capacity of actual connection systems which were subjected to similar biodeterioration treatments. Significant reductions in the dowel bearing strength of CLT were observed 30 weeks after fungal inoculation. Similar patterns of degradation were observed for both fungi in all three CLT species, but R. placenta was slightly more aggressive than G. trabeum, causing a 16.2 MPa reduction in dowel bearing strength of Douglas-fir after 40 weeks of exposure. Connection capacities estimated using National Design Specification yield models for dowel type fasteners and the dowel bearing strength of fungal-damaged CLT were consistent with observed properties and were within 85% of actual capacity of connections tested, especially in early stages of decay.

Examining the spatial networks of an urban agglomeration through the lens of multi-dimensional element flow: Evidence from western China

The Chengdu–Chongqing urban agglomeration (CCUA), as the only national-level city cluster in southwestern China, serves as a strategic support for the Yangtze River Economic Belt and an important demonstration area for promoting new urbanization in the country. The study of the networked characteristics of the CCUA contributes to a systematic understanding of its spatial connectivity patterns, optimization of spatial structure and layout, and promotion of high-quality regional development. In this study, we constructed models for traffic flow, information flow, migration flow, and composite flow to calculate the strength of connections between cities and the total flow of various elements in the CCUA. ArcGIS spatial visualization tools were used to depict the spatial connectivity patterns of the element flows within the CCUA. Additionally, social network analysis methods, including network density, centrality, and cohesive subgroups analysis, were employed to reveal the spatial network structure characteristics of the CCUA. The findings are as follows: (1) The overall structure of the cities within the CCUA is relatively loose, with significant differences in connectivity strength. It exhibits a west-strong and east-weak pattern, with Chengdu-Chongqing, Chengdu-Deyang, Chengdu-Mianyang, and Chengdu-Meishan occupying the top tier, while Zigong and Ya'an have relatively weak connections with other cities. Chengdu and Chongqing have prominent positions in the CCUA, with Chengdu having a more prominent core position compared to Chongqing, resulting in an overall hierarchical distribution of “1 + 1+7 + 7”. (2) The network density of the element flows in the CCUA is relatively low, indicating a generally weak element connectivity. The centrality of cities other than Chengdu and Chongqing is at a moderate to lower level, suggesting a weak overall resource connectivity capacity in the CCUA. (3) Most cities tend to form cohesive subgroups based on geographic proximity, while the cohesive subgroup in Chongqing is still in its early stages of development due to administrative boundaries. The research results quantitatively depict the spatial network structure characteristics of the CCUA, providing theoretical references for its development.

Component Modeling for Fire Behavior of Shear Tab Connections

During a building fire scenario, the behavior and capacity of gravity connections can significantly contribute to the integrity of steel-framed building structures. Because gravity connections are subjected to axial and flexural force demands and have a limited rotational capacity due to large beam rotations during a fire scenario, a connection model is needed to simulate their behavior when using analytical models to simulate the behavior of a steel structure in fire. This study develops a component model for shear tab connections at ambient and elevated temperatures in the opensource finite element program, OpenSees, to further enable the use of OpenSees for simulating steel structures in fire. Although the developed component model is not limited to implementation within OpenSees. The developed component model is benchmarked against experimental tests of isolated connections and a structural assembly with shear tab connections subjected to mechanical and thermal loads. Through benchmarking, it is shown that (1) the developed component model could be used to simulate connection behavior during a fire scenario and (2) simulating the ductility of connections and connecting components due to damage is critical when simulating the behavior of shear tab connections exposed to fire.

Bolted end-plate tube connections subject to tension and bending

A large amount of research has been undertaken on tubular bolted end-plate connections loaded in axial tension, and considerably less on such connections in flexure. This paper studies the combined effects of these two loads and presents the first laboratory tests on these connections under combined tension and flexure. Using validated finite element models, a parametric study with 360 numerical models is performed on these connections under axial and eccentric tension loads. After screening this database of experimental tests and numerical results to isolate only connection failure modes, current design methods for predicting the connection capacity under eccentric tension are evaluated and revised. In addition, based on interaction curves, a novel approach is proposed to design these splices under combined loads. For all methods, the use of the plate ultimate and yield stress was compared for the end-plate material strength parameter. Lastly, a reliability analysis is performed for the application of the recommended design methods to Canadian practice.

A cyclic GTN model for ultra-low cycle fatigue analysis of structural steels

Ultra-low cycle fatigue (ULCF) is a critical concern in the seismic design of steel structures due to its adverse effects on the ductility and energy dissipation capacity of steel connections. The Gurson-Tvergaard-Needleman (GTN) model, a well-accepted micromechanical fracture model, cannot be applied directly to ULCF analysis, as it requires proper estimation of the effects of cyclic loadings on the ductile fracture of materials. In this paper, a cyclic GTN (C-GTN) model was proposed for the ULCF prediction of materials, in which the evolution of microvoids during ULCF loadings was addressed for tensile and compressive half load cycles, respectively, and the effect of the cumulative plastic strains on the material’s resistance to ductile fracture was considered by the reduction of the critical void volume fraction for void coalescence. Then, a VUMAT subroutine was programmed for the C-GTN model, in which the cyclic hardening behavior of materials was simulated with the Voce-Chaboche model. Finally, the C-GTN model was calibrated for the G20Mn5QT cast steel based on previous tests on notched round bar specimens of the material. The applicability of the C-GTN model and the VUMAT subroutine were validated in the ULCF analysis of double-hole plate specimens of the G20Mn5QT cast steel.

Localised pull-through failures of cold-formed steel batten screw connections under combined wind and sub-zero temperature conditions

The utilisation of thin cold-formed steel (CFS) elements is widespread in contemporary lightweight building construction. Roof and wall cladding systems are predominantly made of thin, high-strength steel claddings and battens. Blizzards are predominantly observed in North American countries, resulting in significant roof damage. A localized pull-through failure mechanism, occurring at the batten to rafter/truss screw connections, has been extensively investigated at ambient temperature to comprehend the critical factors that influence the pull-through failure capacities of CFS battens. Nonetheless, the pull-through capacity of CFS battens at sub-zero temperatures has not been examined, and as a result, the performance of the steel cladding systems during blizzards under the combined action of strong winds and sub-zero temperatures remains unknown. To investigate the pull-through failure behaviour and capacities of batten screw connections, an experimental study comprising 96 tests was conducted involving two steel grades and three thicknesses of steel battens and two screw fasteners at sub-zero temperatures. The study was conducted at both ambient and sub-zero temperatures to understand the pull-through failure behaviour and capacities of batten screw connections. Appropriate pull-through capacity equations and associated increment factors were developed to predict the pull-through capacities of batten screw connections that are subjected to the combined effects of high wind uplift loads and sub-zero temperatures.

Experimental investigation of rigid khorjini connections using reduced beam sections with diagonal and horizontal-vertical stiffeners

Steel structures with khorjini beam–column connections, used to be a popular construction practice in Iran. This paper presents a new rigid khorjini connection with reduced beam sections (RBS) for earthquake-resistant steel structures. In rigid khorjini connection, two beams pass next to the column faces without interruption and are connected to the column by vertical plates. In this research, Rigid khorjini connections with Reduced beam sections were investigated. RBS method has some disadvantages such as web local buckling and lateral torsional buckling. Therefore, to prevent these weaknesses and improve the performance of khorjini connections with reduced beam sections, web stiffeners were employed. Four different specimens were constructed and tested using IPE 140 profiles for beams: one without an RBS (KHORJINI), one with reduced beam section (KRBS), and two with RBS and web stiffeners (KRBS-HVS and KRBS-DS). Through these experimental tests, it was revealed that all specimens sustained the interstory drift angle greater than 0.06 rad without any significant loss of strength, which indicates that the Rigid khorjini connection with reduced beam sections for IPE140 profiles can perform acceptably under the conditions of AISC regulations and the use of Diagonal and Horizontal-Vertical stiffeners increased the energy dissipation and plastic rotation capacity of connections.

Experimental study of innovative bolted shear connectors in demountable cold-formed steel–concrete composite beams

Although cold-formed steel (CFS) members have been widely used in structures, their application is limited due to the buckling and instability of these members. To enhance their strength and stiffness, they are often combined with other materials like concrete or timber. One of the main challenges in composite structures is ensuring proper connection between different components to facilitate safe shear load transfer. This is achieved through various types of shear connectors. Bolted shear connections are preferred over headed shear studs because they offer greater strength and can be easily dismantled. Headed shear studs welded onto a steel section are unsuitable for CFS members due to their low thickness.In this paper, we propose a novel demountable composite connection specifically designed for prefabricated CFS structures. The behavior of this connection was evaluated through fifteen push-out test specimens, with key variables including CFS section thickness and bolt diameter/strength. The ultimate load, stiffness, ductility, and failure modes of all specimens were determined. The results revealed that specimens with a higher thickness of CFS members experienced bolt fracture, exhibiting superior effective stiffness, strength, and ductility. Conversely, specimens with a lower thickness of CFS members failed due to distortional buckling of the CFS members. The test results underscore the importance of carefully designing and providing a proportionate CFS section thickness to ensure shear connectors fracture before the CFS members. This significantly improves the shear strength capacity of the composite connection with CFS sections and precast concrete slabs. Furthermore, the deconstructability of the connection at the end of its service life was investigated. The steel–concrete composite connection with precast concrete slabs and demountable bolted shear connections was also modeled using a 3D finite element method. The numerical model’s accuracy in simulating the observed structural behavior was confirmed against experimental data. Finally, appropriate and straightforward formulations for predicting the ultimate load of the CFS-concrete composite connection were proposed. It was concluded that the predictions of ultimate shear load capacity values by EC4, AISC, and AISI provisions for this composite connection are significantly less accurate.

Experimental study of novel wrapped CFRP-strengthened CFS-to-sheathing screw connections

Cracking damage of the sheathing wallboards in screw connections is the typical failure mode of cold formed steel (CFS) structures under seismic effects, which limits the shear capacity and weakens the hysteretic performance of CFS structures. To improve the shear performance of CFS-sheathing screw connections, a novel screw connection with carbon fiber reinforced polymer (CFRP) reinforcement is proposed in this paper. Cyclic tests were conducted on a total of 26 sets of screw connections with different configurations and wall sheathings, and the effects on the failure modes and shear performance of the connections with and without CFRP reinforcement were investigated. The strengthening effects of the sheathing material, panel thickness and end distance on the shear properties of the connections were discussed. The results indicated that (1) except for specimens with 15 mm end distance, CFRP reinforcement can effectively avoid brittle cracking failure of the connections, and the failure mode tended to ductile failure of the bearing and pull-through damage. (2) in addition to the stiffness, the shear strength, deformation capacity, ductility and energy dissipation capacity of CFRP-strengthened connections are significantly enhanced. The effect of CFRP on the shear performance improvement of connections sheathed with gypsum board (GWB) and magnesium glass board (MgO) is greater than that of oriented strand board (OSB), and the strengthening effect is not significantly influenced by the board thickness. A toughness evaluation method for CFRP-strengthened connections was proposed, and the design formulae for the shear strength of the CFRP-strengthened screw connections were recommended based on the load resistance factor design (LRFD) method and allowable strength design (ASD) method.

Finite element modeling and design equations of partially steel-reinforced concrete beam-to-steel tube column joint

Steel reinforced concrete beams are increasingly used as novel transfer structures in high-rise buildings. In this paper, numerical and theoretical studies were carried out on a novel joint of steel-reinforced concrete beam and steel tube column, in which the beam was reinforced by a short steel beam with partial length. Based on the previous experimental studies, finite element modeling was performed to consider the evolution of the concrete damage and to investigate the effects of the main design parameters on the seismic performance of the new joint. It was found that the length of the steel shape, the thickness of the concrete cover, and the concrete compressive strength have significant effects on the initial stiffness and peak capacity of the new joint, while changing those parameters may not change the failure mode of the joint. A theoretical analysis was performed to establish an analytical model for the shear capacity of the new connection that takes into account the contributions of the steel web, stirrups, and concrete. The model was verified against the database of experimental and numerical analysis results. Design equations and recommendations for checking the flexural and shear strength of the embedded steel shape, the composite beam and the RC part of the beam were also provided.

Investigations on the system reliability of composite beams by transferring brittle and ductile Daniels systems to the shear connection

AbstractIn the design of a composite beam, the load‐bearing capacity of a shear connector is assumed to have its design value PRd. But a shear connection consists of dozens to hundreds of connectors whose individual capacities are scattered and randomly distributed. Thus, the load‐bearing capacity of the shear connection is usually higher than the capacity assumed in design n · PRd.In 1945, H. G. Daniels described the system reliability of ideal elastic‐brittle fibre bundles with force redistributions after failure of individual fibres. In many cases the system reliability increases for few elements. And it increases continuously for ductile elements.This article shows a reliability analysis of ideal Daniels systems with brittle and ductile elements. For the shear connection, the ideal Daniels system is extended to unequal load distributions in the shear connection of a composite beam. In parameter studies, the influence of the number of connectors on the system reliability of the composite beam is investigated for different boundary conditions. Again, an increase in reliability can usually be observed with only a few shear connectors. Conversely, if the reliability should remain the same, the design level of the shear connection could be raised by adjusting the partial safety factor γV.

Recent progress in computational predictions on fatigue and fracture resistance of steel connection joints

AbstractSteel structures are often subjected to cyclic loads, and sometimes to monotonic overloads, during the technical lifetime, which causes their performance degradation. Incidentally, they undergo progressive collapse, especially due to local failure of connections or joints. To ensure the overall integrity of the steel structures and to make sure the efficient transfer of the load between different components, it is necessary to evaluate the ultimate capacity and fatigue resistance of steel connections. Advances in material modelling and well‐controlled experiments at various scales in recent years have increased confidence in the finite element method as an effective way to predict the ultimate resistance and fatigue life. On examples of two common steel connections: bolted connection and welded connection, the recent progress will be presented in ductile fracture and fatigue crack initiation and propagation simulation.

Predicting punching shear in RC interior flat slabs with steel and FRP reinforcements using Box-Cox and Yeo-Johnson transformations

This study presents a new approach for predicting the punching shear strength of reinforced concrete flat plates reinforced with steel and fiber-reinforced polymer (FRP) bars, using four machine learning regression models. A dataset of 505 interior flat plates from previous literature was used to develop the models. Input variables were transformed using Box-Cox and Yeo-Johnson transformations to improve predictive power by reducing white noise. The SHapley Additive exPlanations (SHAP) framework was utilized as the Explainable Artificial Intelligence (XAI) method to decipher model execution and feature the main info factors for anticipating the punching shear capacity. Additionally, design codes and equations from the literature are compared to the efficiency and accuracy of the power transformation featured XGBoost model. The findings demonstrate that the suggested prediction model performed very well and is appropriate for estimating the punching shear capacity of slab-column connections reinforced with steel and FRP bars. Moreover, the power transferred XGBoost model performed better than other numerical equations because it had the highest mean R2 (0.93) and lowest MAPE (0.20) for testing, which suggests that machine learning models may be able to offer an elective strategy to currently used mechanics-based models for configuration practice.

Climate change–induced stress disrupts ectomycorrhizal interaction networks at the boreal–temperate ecotone

The interaction networks formed by ectomycorrhizal fungi (EMF) and their tree hosts, which are important to both forest recruitment and ecosystem carbon and nutrient retention, may be particularly susceptible to climate change at the boreal-temperate forest ecotone where environmental conditions are changing rapidly. Here, we quantified the compositional and functional trait responses of EMF communities and their interaction networks with two boreal (Pinus banksiana and Betula papyrifera) and two temperate (Pinus strobus and Quercus macrocarpa) hosts to a factorial combination of experimentally elevated temperatures and reduced rainfall in a long-term open-air field experiment. The study was conducted at the B4WarmED (Boreal Forest Warming at an Ecotone in Danger) experiment in Minnesota, USA, where infrared lamps and buried heating cables elevate temperatures (ambient, +3.1 °C) and rain-out shelters reduce growing season precipitation (ambient, ~30% reduction). EMF communities were characterized and interaction networks inferred from metabarcoding of fungal-colonized root tips. Warming and rainfall reduction significantly altered EMF community composition, leading to an increase in the relative abundance of EMF with contact-short distance exploration types. These compositional changes, which likely limited the capacity for mycelial connections between trees, corresponded with shifts from highly redundant EMF interaction networks under ambient conditions to less redundant (more specialized) networks. Further, the observed changes in EMF communities and interaction networks were correlated with changes in soil moisture and host photosynthesis. Collectively, these results indicate that the projected changes in climate will likely lead to significant shifts in the traits, structure, and integrity of EMF communities as well as their interaction networks in forest ecosystems at the boreal-temperate ecotone.

Nonlinear analysis on mechanical behaviour of high strength steel extended endplate connections and equivalent T-stubs in fire considering axial force

In fire, ignoring the axial force acting on the high strength steel (HSS) beam-column endplate connections when considering catenary action may lead to a safety risk for the whole steel structure. Hence, a nonlinear analysis is conducted to reveal the actual performance of HSS T-stubs and HSS extended endplate connections in fire using the software ABAQUS. The ultimate displacement, failure mode and bearing capacity of HSS T-stubs under tension-shear combined action are investigated. The failure modes and moment–rotation curves of HSS endplate connections obtained by the numerical study are verified with test results in fire. Furthermore, the effects of bolt diameter, endplate thickness, endplate strength, the combination of endplate thickness and endplate strength, as well as temperature on the mechanical behaviour of HSS endplate connections considering axial force are studied. The results of nonlinear analysis are verified against Eurocode 3 Part 1–8 in various situations. The results indicate that when the shear-to-tension ratio is 2.0, the tensile bearing capacity and ultimate displacement of HSS T-stubs at 600 °C decreased to 38% and 31% of the pure tension, respectively. The parametric analysis shows that when the temperature is 600 °C, the initial stiffness and ultimate flexural capacity of connections are only about 40% and 31% of that at 20 °C.

Mountain passes are higher at low latitudes for madicolous insect communities of the Neotropical region

AbstractAimTo test whether spatial turnover patterns of mountain madicolous insect communities in the Southern Hemisphere support the ‘mountain passes are higher in the Tropic’ hypothesis (MPHT). To do this, we compared madicolous communities in the Amazon Mountains (equator) and the Atlantic Forest Mountains (23°S).LocationBrazil.MethodsWe characterized madicolous insect communities in two elevational gradients between 90 to 3000 m a.s.l. separated by 23° of latitude, totalling 108 sampling sites. Since the MPHT predicts a more intense turnover along elevational gradients at lower latitudes than at higher latitudes, we evaluated beta diversity in the Amazon mountains, at the equator, and in the Atlantic Forest mountains, in the subtropical region. We quantified multiple‐site abundance‐based dissimilarity to assess whether beta diversity was different between both regions. We also performed constrained ordination (db‐RDA) analyses to assess whether community dissimilarity (balanced variation in abundances) was uniquely or jointly explained by environmental, spatial and/or elevational predictors. Additionally, we independently assessed the relationship between community dissimilarity and altitudinal difference in each region and tested for differences in model parameters between regions.ResultsAlthough we found high species turnover in both regions, the community variation explained by environmental factors and altitude was higher in the Amazon than in the Atlantic Forest, as evidenced by db‐RDA and altitudinal difference models. In general, communities were remarkably constrained by spatial predictors, which result from low dispersion capacity of most madicolous insects and low connectivity of madicolous systems. Consequently, the composition of madicolous insects notably diverged between regions, highlighting the complementarity and high conservation value of both systems.Main ConclusionsOur results indicate that the MPHT explains, at the community level, the differences between low‐ and high‐latitude mountain systems in community turnover along elevational gradients, even within a relatively short latitudinal distance in the Southern Hemisphere.

Tensile behaviors and configurations of double-headed bar overlap connections for precast concrete members

The superiorities in construction time, cost, and quality of precast RC structures are accompanied by the challenges in connection, particularly in steel bars connections between RC components. The extensively used steel bar connections for either grouted sleeve splice connection or grouted spiral-confined lap connection requires on-site grouting, which is a concealed construction process with increased the risk of grouting defects, thereby impairing connection reliability. The confined headed bar connection (CHBC) with visible on-site construction has been proposed to address the unseen grouting defects concerns. However, modern structures that use large-diameter or high-strength rebars present higher demands for steel bar connection capacity. For CHBC, it is suggested to use either a long connection length or a large-size head to satisfy the capacity demand. However, the long connection length can increase field wet operation, which is disadvantage in precast concrete construction. The large-size head can help reduce the connection length, but it can cause inconvenience including construction congestion and the increased eccentric bending moment under tension. This paper presents the CHBC with double-head configuration, which can reduce the single head size. The proposed CHBC consists of confinement stirrups and two overlapped headed bars and the stirrup confining the core concrete can also improve the CHBC capacity. Experimental investigation on 21 CHBC specimens has been carried out. The failure modes, bearing capacity, and stirrup strain development have been studied. Effects of the double-head configuration and confinement stirrup ratio have been analyzed through experimental and numerical investigation. Results show that the double-head configuration has a minor impact on the tensile capacity of CHBC while the increase of confined stirrup ratio can improve the tensile capacity of CHBC. Configuration details of size and spacing for stirrup reinforcement in CHBC are proposed. Based on the test results, CHBC tensile capacity prediction method is suggested, which can take the head configuration into account.

Enhancement of outage probability for down link cooperative non-orthogonal multiple access in fifth-generation network

<span lang="EN-US">Future wireless networks are expected to face several issues, but cooperative non-orthogonal multiple access (C-NOMA) is a promising technology that could help solve them by providing unprecedented levels of connection and system capacity. In this regard, the influence of the power location coefficient (PLC) for remote users adopting multiple-input-multiple-output (MIMO) and massive MIMO has been explored to provide effective performance. The goal of this study is to design fifth-generation (5G) downlink (DL) NOMA power domain (PD) networks with a variety of distances and PLCs for remote users and then to compare their outage probability (OP) performance versus signal to noise ratio (SNR). As a novel approach to improving OP performance rate and mitigating the influence of the PLC for remote users, DL C-NOMA is combined with 16×16, 32×23, and 64×64 MIMO and 128×128, 256×256, and 512×512 massive MIMO. The results were obtained that the 64×64 MIMO improves the OP for the remote user by 65.0E-03, while the 512×512 massive MIMO achieved an improvement that reaches 1.0E-06 for the PLC of 0.8 at SNR of 14 dB. The Rayleigh fading channels and MATLAB simulation tools were utilized to carry out the study work.</span>

Perancangan Absensi Berbasis Web Dengan Metode Waterfall (Studi Kasus: PT. GlobalRiau Data Solusi)

Employee attendance is an important activity for the company because it can affect the amount of revenue. In implementing the recording procedure, this attendance requires accuracy in order to produce a good attendance report. PT GlobalRiau Data Solution (GDS) is a company or industry that provides Internet connections and other related services. GDS has a communication infrastructure connected to the Internet, where GDS then shares its network connection capacity with customers who need network connection services. Previously, attendance at PT.GDS was carried out manually within the company, but this manual process had many obstacles, including manipulation of attendance even with ineffective data storage. Therefore, the research aims to design a website-based attendance system or attendance recording using the waterfall method so that it can improve the attendance process to be more efficient. Web technology is used because it offers advantages, such as being able to work on any system as long as there is an internet connection and does not require a computer with a high capacity to run a web application while the use of the waterfall method is applied sequentially and systematically. The waterfall method begins design to maintenance and is implemented in stages.