Main Construction Research Articles

Main cable structure analysis and construction control of short span suspension bridge within three-tower

The Feng Chu suspension bridge in Xiangyang holds the distinction of having one of the shortest span lengths among global suspension bridges, measuring less than half the length of conventional designs. This paper focuses on the engineering background of the bridge and delves into the analysis of the main cable structure and construction control methods for short-span suspension bridges with three towers. The study examines the impact of elastic modulus deviation in the main cable and the dead-load error of the stiffening beam on key parameters such as the unstressed length of the main cable, pre-deflection of the cable saddle, and mid-span elevation of the empty cable. Additionally, the effects of temperature, span, and cable length on the sag of the empty cable during the erection process are analyzed. Findings reveal that the elastic modulus and dead-load error significantly influence the unstressed length of the main cable, pre-deflection of the saddle, and the shape of the empty cable. This study establishes a relationship between changes in cable length and mid-span sag, providing valuable theoretical guidance for aligning and adjusting the main cable strands. Furthermore, synchronized alignment adjustments for the two mid-span sections are proposed to prevent main cable strand sliding, which may occur due to significant differences in sag between the sections.

Thermomechanical characteristics of a thermally inactive neighboring pile of an energy soldier pile during constraint changes

This study aims to determine whether it is worth activating energy soldier piles during the excavation and construction phases by investigating the thermomechanical response of a thermally inactive neighboring pile subjected to thermal loads resulting from an energy soldier pile in a foundation pit support system. This was achieved through a field test utilizing constant-power heating. The energy soldier piles under investigation are susceptible to constraint changes due to the installation and removal of internal supports. The impacts of temperature and constraint changes during excavation and main structure construction on thermally inactive neighboring piles are analyzed and discussed. The results indicated that the maximum temperature difference along the depth direction of the thermally inactive neighboring pile during the construction of the main structure was 9.7 °C, whereas during the excavation, it was 13.9 °C. The constraint on the excavation side transitioned from a continuous state to a concentrated state with a point-like distribution, and finally to a continuous state of restraint for the large-stiffness main structure. The maximum thermally induced stress was 0.283 MPa/°C. During the excavation stage, the degree of freedom in the middle of the pile was approximately 0.8. Following backfilling, this value decreased to 0.3. Additionally, the maximum horizontal displacement moved to below the bottom elevation of the main structure, and none of the maximum values exceeded 3 mm. Since thermal activation during the excavation and construction processes can lead to issues with no real benefit, activation of the energy piles during these phases is not necessary, and better benefits are obtained by activating the energy soldier piles during the operation phases of the internal building.

Analysis of carbon emission characteristics and establishment of prediction models for residential and office buildings in China

Intensifying environmental issues make carbon reduction crucial, especially in the construction industry. Embodied carbon emissions (ECE) in buildings characteristically involve concentrated, intensive emissions over a short period. Implementing energy-saving and carbon-reducing technologies has raised ECE rates. Therefore, analyzing carbon emission (CE) characteristics during the production and construction phases is necessary. Currently, essential data on ECE is lacking, the calculation methods are complex, and ECE's characteristics and influential factors in residential and office buildings remain unclear. Moreover, there is a lack of prediction models for ECE in the construction phase that apply to current construction methods and CE factors. The research on prediction models for ECE has primarily focused on the production phase but has paid little attention to the contribution of non-structural materials to embodied carbon (EC). In this study, reinforced concrete residential and office buildings in hot summer and cold winter regions (located in the southeast part of mainland China, with a subtropical monsoon climate) were considered typical types, and the CE characteristics of two main phases, the production and construction phases, were analyzed. Based on critical features, such as the number of floors and the basement, prediction models for ECE in residential and office buildings were established at the design stage. The models were validated with mean absolute percentage error (MAPE) values below 4%, and coefficient of variation (root mean square error) (CV [RMSE]) values less than 0.02. The prediction models enabled a rapid estimation of ECE, encouraging designers to consider EC in the early design stages.

Specific and shared cognitive predictors of drawing and block building in typically developing children.

Spatial construction is a complex ability involving attention, global/local visual processing, mental representation, visuo-motor coordination and, to varying extent, working memory and executive functions, and verbal abilities. In developmental neuropsychology, little attention has been paid to comprehend whether and to what extent the above cognitive processes are involved in two main spatial construction tasks, that is drawing and block building. We used path analysis to test shared and specific effects of verbal and spatial working memory, spatial attention, inhibition, verbal abilities (vocabulary and naming), figure disembedding, mental rotation, and visual-motor coordination, as well as of demographics (sex, age and socio-economic status), on two classical drawing (Rey-Osterrieth Complex Figure; ROCF) and block building (Block design; BD) tasks in a sample of 195 typically developing children (age range: 7-11 years). Figure disembedding and visuo-motor coordination were the only shared predictors of both spatial construction tasks. Moreover, ROCF score was directly related with spatial attention and inhibition, while BD score was directly related with sex, vocabulary, mental rotation and backward spatial working memory. These findings distinguish between abilities involved in spatial construction regardless of the type of task and those specifically related to ROCF or Block Design, thus providing clues relevant to neuropsychological assessment and intervention in children with spatial construction disorders.

Structural evolution and exhumation events recorded in the Huingancó Granodiorite, Cordillera del Viento, Southern Central Andes, Argentina

This study seeks to unravel the exhumation history of Permian granodiorites corresponding to the Huingancó volcano-plutonic Complex in the southern sector of the Cordillera del Viento (∼37°S), located within the Chos Malal fold-thrust belt. In this context, mineral chemistry analyses were conducted on the granodiorites using electron microprobe data to infer the P-T conditions of emplacement, resulting in 700–900 °C and pressures ranging between 1 and 2.4 kbar. Employing a geostatic gradient of 3.7 km/kbar, these values give an estimate of emplacement depths between 4 and 9 km. In order to understand their exhumation path, five samples from the Huingancó Granodiorite were taken along the Huaraco creek on the western flank of the Cordillera del Viento anticline to perform apatite fission track (AFT) analysis. This analysis yielded new cooling ages for the study area ranging between 50 and 80 Ma. Furthermore, inverse thermal modeling using the fission track data revealed two significant exhumation events during the Andean cycle: one during the Late Cretaceous-Paleocene and the other in Miocene times, separated by a period of gradual cooling or stability during Eocene-Oligocene times. These important cooling events are associated with the main construction phases of the Cordillera del Viento. Finally, to characterize its deformation evolution, a structural kinematic model is proposed based on a balanced structural section and its reconstruction to its non-deformed pre-Cretaceous state. The resulting model allows us to identify the structures and mechanisms of uplift rising the Cordillera del Viento, and their association with the main exhumation events depicted in the inverse thermal modeling. The main structure of the Cordillera del Viento corresponds to a fault bending fold that involves the basement in the deformation. Subsequently, its insertion as an intracutaneous wedge is related with the development of the thin-skinned structures at the internal sector of the Chos Malal fold and thrust belt.

Transitioning from inhibition to contextual emergence: investigating the mechanisms underlying the marginalization of county-level public libraries in China

PurposeThis study aims to uncover the mechanisms behind the marginalization of county-level public libraries.Design/methodology/approachThe research surveyed 25 counties in central China, including Hubei, Chongqing, Hunan, and Guizhou provinces. Semi-structured interviews were conducted with library directors and deputy directors, focusing on main and branch library construction, cultural inclusivity, library assessment, and digital services.FindingsContributing factors to library marginalization were identified as economic pressure, institutional domain, longstanding issues, organizational entity, and societal misconceptions. Building on this, the study introduces the HBAC model to explain county-level public library marginalization. Considering the actual social context of these libraries, the article proposes a “3 + 1” approach to mitigate their marginalization.Originality/valueThe research methodology, analysis process, theoretical model, and recommendations provided could shed light on academic research and practical exploration in the field of public libraries globally.

SPPs based nano refractive index sensor for sodium and potassium ion concentration detection in human blood

In this paper, a micro-nano sensing configuration constructed from MIM waveguide and a semicircular cavity with annular cavity (SCAC) based on surface plasmon polaritons(SPPs) is submitted. And the sensing property of the waveguide coupling construction is investigated using the finite element method. The optimization emulation results show that the broadband mode generated by the two rectangular cavities on the bus waveguide interacts with the narrowband mode generated by the main construction SCAC, and the radiation spectroscopy of the system appears to be significantly sharp and asymmetric, which is the Fano resonance phenomenon. The impact of external environmental changes on the capability of the sensing structure was investigated by altering the geometric argument of the designed structure afterwards. The final system can achieve a sensitivity of 2600 nm RIU−1 and a figure of merit (FOM) of 47.27. It was then applied to biosensing and its sensitivity as a human sodium and potassium ion concentration detection sensor was investigated and the best can be achieved at 0.415 mgdl−1 and 0.525 mgdl−1.

INCREASING FATIGUE LIFE OF NEW WELDED AND REPAIRED JOINTS BY HFMI TREATMENT

AbstractThere is a growing number of welded steel bridges in the world that are reaching the end of their design life. Repair of fatigue damage (cracks) or replacement with new modern designs is becoming an increasing issue. Fatigue damage is now one of the main design and construction risks associated with the construction of new dynamically stressed steel structures. Fatigue damage is now one of the main design and engineering risks associated with the construction of new dynamically stressed steel structures. Increasing fatigue life can be achieved by HFMI treatment that can be applied to new weld as well as existing welded joints. This paper presents the results of experiments focused on HFMI treatment to new and repaired butt welds of higher thicknesses.

Life Cycle Assessment Analysis Based on Material Selection in Sustainable Airport Buildings

Sustainable airport buildings aim to minimize environmental impacts through energy efficiency, water conservation, and waste management. This is achieved by employing green building materials and utilizing renewable energy sources to reduce their carbon footprint. In this study, life cycle assessment (LCA) was conducted to assess the environmental impacts of three main construction materials—concrete, steel, and wood—used in sustainable airport buildings. These materials were selected for their widespread use in eight different airport terminal buildings with sustainability certifications. The environmental impacts of these materials were calculated and compared using OpenLCA 1.9.0 software and the ECOinvent database, adhering to the standards set forth by the Environmental Product Declaration (EPD) initiative. The findings indicate that wood, as a construction material, has a significantly lower impact on global warming compared to steel and concrete, with a global warming potential (GWP) ratio of less than 60%. Steel, with a GWP of approximately 90% of that of concrete, also showed a lower impact than concrete. Additionally, other environmental impacts, such as stratospheric ozone depletion potential (ODP) and acidification potential (AP), were also examined, highlighting the trade-offs associated with each material.

Continuous Slag Discharge Construction Technology for Shield Tunneling in Narrow Space Environment

The shield tunneling method is the main construction method in subway tunnel construction, which has the characteristics of safety, efficiency, mechanization, and high degree of automation. However, the shield tunneling equipment is huge, the supporting facilities are numerous, and the site requirements are high. In response to the problems of slow slag removal speed and low construction efficiency in shield tunneling under the construction conditions of small wellhead shield tunneling sections in urban subways, taking the shield tunneling section of Guangzhou Metro Line 13 Phase II as the background,This article introduces the main components, working principles, installation and transportation processes, fault handling, and benefit analysis of the continuous belt conveyor slag removal system,This article elaborates on the method of using a continuous belt conveyor in the tunnel combined with a vertical lifting system at the wellhead to achieve continuous slag removal during underground shield tunneling construction in a narrow wellhead construction site. This not only improves excavation efficiency but also reduces construction costs, solves construction problems, and provides reference for similar projects in the future.

Concept for recycling a small-scale plastic-based bioreactor in a close-loop – Technical approach

To accelerate biotherapeutic development whilst decreasing development time and project cost, small-scale multi-parallel bioreactors have been developed to maximize product yield and quality. These systems feature single-use plastic-based bioreactors for easy connection and fast turnaround. Despite well-known advantages, the perception of plastic and the lack of recycling options are raising concerns in the scientific laboratories’ community. One of the common objections to plastic circularity in life-science is the perceived “downcycling” effect of mechanical recycling. Therefore, the aim of this work was to establish the technical feasibility of a close-loop recycling concept for the main construction material of the small-scale bioreactor. Application tests (cell compatibility and cell culture) were performed and supported by quantitative physical and mechanical tests (tensile, melt flow index, light transmission). Results show that mechanically recycled polycarbonate could be re-used in the same application. A comparative life cycle assessment (LCA), based on a theoretical framework, showed with different scenarios that recycling would have a positive impact on Climate – Carbon – total within the boundaries. Even if the technical feasibility of such a concept is demonstrated through this study, several challenges remain for such a closed-loop recycling concept to be implemented at a commercial scale.

Analysis of Critical Instability Conditions for Solid-Phase Plugging of Natural Fractures during Temporary Plugging and Fracturing.

Hydraulic fracturing has become a key technology for the development of unconventional oil and gas resources, such as deep shale. Due to the development of natural fractures in deep shale reservoirs, the opening of natural fractures during the fracturing process can cause a significant loss of fracturing fluid, resulting in a reduction in the width of the main fracture and construction risks, such as sand plugging. It is important to improve the fracturing effect of deep shale reservoirs by plugging natural fractures with solid phases, reducing filtration, and improving the efficiency of the fracturing fluid. Ensuring the effectiveness of solid plugging is key to optimizing the fracturing design and improving the stimulation effect after fracturing. In this study, solid plugging technology is introduced into the filtration control process of natural fractures. By setting a plugging zone with a certain length and permeability inside the natural fracture, a stability prediction model for the plugging zone of natural fractures is established, and the instability conditions of the plugging zone are analyzed. The simulation results indicate that the instability of the plugging zone is related to permeability and there is a critical permeability. When the permeability of the plugging zone is greater than this value, expansion instability will occur, and when it is less than or equal to this value, shear slip instability may occur. The strength of shear slip instability is mainly determined by the length of the plugging zone, the friction angle of the natural fracture surface, the friction angle between the plugging particles, and the porosity of the plugging zone. The friction angle of natural fracture surfaces affects only the strength of slip instability, while the friction angle of plugging particles and porosity mainly affect the strength of shear instability. The research results provide a theoretical basis for the optimization of fracturing construction parameters in deep shale reservoirs.

Research on methods for controlling strand sag in main cables

The accuracy of main cable construction in suspension bridges is directly influenced by the sag of the strands during the erection process. Thus, effective methods for controlling strand sag are crucial. However, the current control standards and methods are primarily based on practical engineering experience, lacking quantitative analysis and a sufficient basis. This paper aims to address this gap by summarizing four commonly used strand sag control methods and proposing a quantitative analysis model that considers the influence of random factors. The model quantifies the impact of these methods on the main cable shape and strand tension after cable tightening. To illustrate the practical application, a suspension bridge is utilized as a case study. The results of the study illustrate a linear relationship between the main cable sag and inter-strand distance, with each control method exhibiting a varying linear change rate. Moreover, the discrepancy in strand distance contributes to uneven strand tension after cable tightening. Random errors contribute to the dispersion of the main cable sag and strand tension, which are further exacerbated by cumulative errors between layers of general strands. Based on the study’s results, this paper provides valuable references for the erection and control of the main cable in suspension bridges.

Precursors of falls from height in two main contractor companies in the Chilean construction sector and their subcontractors: Shared vision and preventive prioritization.

Risk factors that can result in serious injuries or deaths are frequently not understood or prevented because of the traditional way in which organizations approach safety. This is especially true for falls from heights in the construction sector, which remain a leading safety hazard in construction globally. A theoretical framework derived from a thorough review of international evidence provided the foundation for the conduct of 50 structured focus groups with a total of 209 participants representing construction workers and supervisors in two main Chilean construction contractor companies and their subcontractors. A total of 627 precursors (risk factors), 56 taxonomies (work tasks/activities), and 622 defenses (prevention actions) were identified. These were classified in three macro dimensions and 13 subdimensions in total, providing a comprehensive framework for the origin, manifestation, and neutralization of such precursors. The findings provide a useful framework for understanding of the most critical risks to which workers are exposed and actions to prevent them. This framework should form the basis for the development of practical safety programs and tools such as management and training checklists, and data analysis for early warning signs.

A review on design and construction of the lunar launch/landing infrastructure

With advances in automated construction and deeper Moon exploration missions, the concept of “building a house on the moon” is becoming increasingly feasible. The launch/landing (LL) infrastructure plays a vital role in ensuring the safety of landers and astronauts and should be prioritized for construction. Initially, this review explores the variety of designs used at existing LL sites, analyzing the logic and unique features of each design. It then outlines three main construction methods for landing pads, from material production to basic construction processes. The review also covers experiments related to LL pads, including material, component, and construction testing. Finally, current challenges and future directions for the development of lunar LL infrastructure are discussed, and 3D-printed biomimetic structures are highlighted as a particularly promising option.

Time Histories Finite Element Modelling for Irrigation Canal Stability Analysis under the Effects of Liquefaction in the Sibowi Sigi Regency, Indonesia

Abstract The Gumbasa irrigation canals are one of the water resource infrastructures damaged by the 7.5 Mw Palu-Donggala Earthquake in 2018. Canal reconstruction was performed to restore the function of the irrigation network, supllying a potential area of 8000 ha. Main canal construction is known to pass through areas with liquefaction vulnerability, and seismic factors also play a role in the stability of construction. This study discusses the stability of construction under the influence of earthquake loads on the Gumbasa irrigation main canal in the Sibowi area, Tanambulava district, Sigi Regency. The irrigation main canals are built in a landfill on a subbase soil with the potential for liquefaction. Numerical simulations were carried out using the finite element method under two conditions, namely static and dynamic conditions on soil parameters obtained from the Standard Penetration Test (N-SPT) data obtained previously. Based on the analysis results, depths of 6.5 m to 9 m have partial potential for liquefaction, with no significant decrease in safety factor (SF). In the static analysis, the SF is 1.65 and 2.13. In the dynamic analysis, the SF is 1.64 and 2.12. The vertical displacement is minimum 0.03 m and maximum 0.10 m.

Numerical computation of heat transfer, moisture transport and thermal comfort through walls of buildings made of concrete material in the city of Douala, Cameroon: An ab initio investigation

The buildings of the city of Douala in Cameroon have been experiencing degradation for several decades due to the climate characterized by high humidity and oppressive heat. As a result, large grayish or black stains can be observed on these buildings. We sometimes witness the subsidence of the slab of the balconies, the cracking of the walls and the collapse of the buildings worn by the humidity. These damages are generally caused by infiltration and capillary rise. In addition, it has been demonstrated that people living in damp buildings are at risk of illnesses such as asthma and lung infections. Therefore, the novelty of this work is threefold: (i) it proposes for the very first time a numerical study of the transport of humidity and heat through the porous walls of buildings constructed with concrete material, the main construction material in the city of Douala; (ii) It was determined what level of indoor thermal comfort was appropriate for sleeping inside a real three-dimensional G+1 complex residential building constructed with concrete blocks; and (iii) Using the geographical coordinates, and time data, the sun radiation's direction of incidence was assessed throughout the simulation. The computation was performed using Comsol Multiphysics 6.0 software. The distributions of temperature, relative humidity as well as moisture level were presented at various periods. It appears from the results that face to this high humidity, the concrete material retains a large quantity of water for a considerable periods of time, which weakens the steel reinforcement of concrete which is corroded by rust. The computation of thermal comfort in the 3D building showed that the various rooms of the building were not comfortable during the night since temperature inside the building increased progressively due to diffusion of heat. In addition, the numerical solutions indicated that the energy stored within the walls diffused from the external walls to the internal walls during the night. It was also demonstrated that the walls of the building were warmer than the windows, doors and the roof at the computational times, which simply revealed a greater storage capacity of heat in the concrete blocks material. The findings highlighted that the temperature decreased rapidly in a thickness of 0.06 m of the concrete block during the nine days and this decrease was attenuated in the second part of the thickness of the concrete block (0.14 m).

Simplifying Depression & Anxiety Screening for Patients ≥12 at a Family Medicine Clinic

Introduction: Depression and anxiety are widely prevalent in the US, with more than 1 in 3 US adults reporting symptoms of these conditions. As such, the USPSTF recently issued Grade B recommendations for the routine screening of depression and anxiety in all adults, which is most common done with the Patient Health Questionnaire-9 (PHQ9) and Generalized Anxiety Disorder-7 (GAD7) validated screening tools for patients ≥12. Problem to Address: Though the McLaren Greater Lansing Family Medicine Clinic (MGL FMC) uses the PHQ9 and GAD7 forms, we found our patients were not routinely completing them. Prior to our QI project, MAs would verbally screen patients when rooming them with the PHQ2, the first two questions of the PHQ9. If positive, the patients were given the PHQ9 and GAD7 forms separately, which were reviewed by the provider who would enter the results into the EMR. However, in a spot review, only 20% of patients with +PHQ2s had a documented PHQ9 result in the EMR. To address this, our QI project’s primary aim was to increase our clinic’s depression and anxiety screening rate, with a S.M.A.R.T. goal of screening ≥50% patients ≥12 for depression and anxiety over 1 week, with a secondary aim of simplifying the screening process altogether. Methods & Results: In the “PLAN” stage of our project, we identified barriers to the forms’ completion—how the two forms added to the form burden shared by patients, staff, and providers; we addressed this by combining the PHQ9 and GAD7 onto one page with a corresponding electronic form to document the result in the EMR. During the “DO,” phase of the project, we implemented the new process, which entailed our reception team providing the combined form to all patients ≥12 at check-in for 1 week. In the “STUDY” phase of the project, we analyzed our results and found we had screened 81% of patients ≥12 for depression and anxiety over 1 week using the new form, exceeding our S.M.A.R.T. goal. We also collected feedback from the staff and physicians on the new process: the main positive feedback was that the combined form was less burdensome to administer and interpret than the two separate forms, and the main construction criticism was that providing the form to every patient ≥12 at every visit distracted from other health concerns needing to be addressed. In the “ACT” phase of the project, we adjusted our clinic’s depression and anxiety screening process by continuing to have the MAs verbally screen our patients using the PHQ2, and if that positive, they now provide the combined PHQ9/GAD7 form instead of the two separate forms. Discussion/Conclusions: Combining the PHQ9 and GAD7 onto one page to screen for anxiety and depression is less burdensome for the providers and staff to administer and interpret than two forms separately. Further research is needed on how depression and anxiety screening can be more equitable, how often it should be done, and how providers should best triage positive screens when other health concerns need to be addressed.

ASSESSING THE EFFECTIVENESS OF THE OIL TRUNK PIPELINE CONSTRUCTION PROJECT: A SCENARIO APPROACH

The article is devoted to the development of a scenario approach in assessing the effectiveness of a main oil pipeline construction project. A pressing issue is the formation of an integrated approach to assessing the effectiveness of the oil trunk pipeline construction project, in connection with the impact of various types of risks and uncertainties of the external environment (technical, economic, environmental). Based on this, a particularly important aspect is to study the impact of these various risks on the project and take into account the scenario approach in this (taking into account both the pessimistic scenario and the optimistic scenario for project implementation), which will improve the efficiency of the entire oil trunk pipeline construction project. The methodology proposed by the author, used when assessing the effectiveness of a main oil pipeline construction project, allows us to take into account the predictable uncertainty of the project's effectiveness. Unified integral indicators of the economic effect of the project for all three scenarios were developed on the basis of standardized indicators and their weighted significance. The most effective project for implementation has been identified, taking into account three scenarios, which, depending on one of the three implementation scenarios, will provide the best values of project performance indicators: net present value, profitability index, internal rate of return and payback period.

Precyzyjne wyznaczanie geodezyjne w budowie obiektów inżynierskich z orientacją w określonym kierunku

In the construction practice, there are engineering structures, where some complex requirements in the process of their building have to be meet, e.g., their positioning, geographical orientation and geometric determination. The current publication examines the specificity of geodetic activities, regarding the orientating of the main construction axes of the foundation and the supporting structures of the terrestrial telecommunication antennas in a predetermined direction, for example, in the parallel direction to the geographical meridian. The focus is on the assessment of the accuracy and the choice of appropriate methods and equipment in order to create the required geodetic network, as well as to perform accurate setting out works. The combination of demands, namely for a specific geographic orientation and precise relative accuracy of the setting elements, implies a suitable transition from the ellipsoidal geodetic coordinates to the projection plane of the setting out project. In this connection, the influence of the meridian convergence on the accuracy of the planning setting out works is examined. A mathematical approach is proposed to assess the need of elimination of this factor, depending on the value of the constructional tolerance and the geographic location of the site.The necessary precision for determining the geodetic ellipsoidal coordinates by GNSS (Global Navigation Satellite System) measurements as well as the required accuracy of the planning and elevation setting out works are shown.Using different geodetic methods and tools, a preliminary accuracy assessment approach and the choice of the appropriate coordinate projection and height reference system is also proposed. The real data, which were obtained in different Earth’s locations by the explained methodology, are presented. The established geodetic networks provide orientation of the main construction axes of the bases of the terrestrial communication antennas in the parallel direction to the geodetic meridian with an azimuth standard error - МА = ± 2÷5' (minutеs) and allowable error in distances and eleventions of the setting out elements, respectively - MdS ≤ ±3 mm, Mdh ≤ ± 2 mm.