Technical Code Research Articles

Assessment and rehabilitation of a deteriorated heat pipeline overpass

A deteriorated heat pipeline overpass was subjected to assessment and rehabilitation. Lack of technical documentation, increased loading, and changing design codes had to be taken into consideration. The numerous damages and their origin were identified. Special attention was paid to corrosion at the connection zones, being the result of inadequate paint coating, aggressive environment, and leakages for technological installations. The structure was originally designed according to the design code PN-62/B-03200 from the 1960’s using the permissible stress method. After rehabilitation it was supposed to fulfil current requirements of Eurocodes. Static strength analyses were performed for both codes and the differences between them were noted. The methods for rehabilitation were limited by the requirement of limited intervention and maintaining the structure under service. The applied solution for the strengthening in form of the steel profiles welded to the existing structure is described.

Pandeo lateral de vigas de acero. Análisis comparado de las normas CTE DB SE-A, EAE y EC3

The Basic Document, Structural Safety, Steel of the Spanish Technical Building Code provides mathematical expressions to obtain the lateral buckling resistance of hot-rolled steel beams. These expressions include a coefficient, {\displaystyle C_{1}}, that accounts for variation of the bending moment along the beam. However, this document only provides values for linear diagrams of bending moments. The instruction for Structural Steel, a copy of the latest version of Eurocode 3, does not include any method to obtain the elastic critical moment. On the contrary, a table with correction factors applicable to different types of bending moments diagrams is included. In this document both procedures have been combined and results have been compared to those obtained using other versions of the Eurocode 3. Finally, tables have been provided to ease the design of hot-rolled steel beams while preventing the lateral buckling.

Primary Energy Balance driven Integrated Energy Design Process of Positive Energy Building

The ISO 52000–1:2017 is the overarching Energy Performance of Buildings (EPB) standard, providing the general framework of the EPB assessment. It is applicable to the assessment of overall energy use of a building, by measurement or calculation, and the calculation of energy performance in terms of primary energy or other energy-related metrics. ISO 52000–1 provides general profound guidelines, but also gives the freedom to adapt the guidelines with national standards and regulations. This article focuses on design stage energy performance assessment in the framework of syn.ikia project, which aims to deliver a blueprint for an Integrated Design Process of sustainable plus energy buildings and neighbourhoods, leading the way to plus energy districts and cities. This project has four demonstration sites and the one being in focus of this article is located in Catalonia, Spain. Even though this project and Spanish Technical code both are based on ISO 52000–1, the criteria of calculation boundaries of those two vary in some degree, and that can cause great difference in the primary energy balance. In the calculation of the energy balance the criteria of syn.ikia considers all common energy uses in a building, including heating, cooling, ventilation, dehumidification, domestic hot water and lighting, while the Spanish Technical Code excludes lighting consumption. The main difference however is caused due to the fact that in syn.ikia hypothesis the exported energy is being considered in the calculation of how much non-renewable energy is avoided from the grid, while Spanish Technical Code excludes it. For the evaluation of these differences, a simplified monthly primary energy calculation tool is developed during the evaluation framework of key performance indicators of the project. The analysis of the calculation framework hypothesis is presented, analyzing the effects of the assessment boundaries, different primary energy balance calculation hypothesis and building design alternatives.

Development of a Reduced Order Model of Solar Heat Gains Prediction

The aim of this study was to elaborate and validate a reduced order model able to forecast solar heat gains as a function of the architectural parameters that determine the solar heat gains. The study focused on office buildings in Catalonia and Spain and their physical values were taken from the Spanish Building Technical Code and European Union Directive 2018/844. A reduced order model with three direct variables (solar heat gain coefficient, shade factor, window to wall ratio) and one indirect design variable (building orientation) was obtained and validated in respect to the International Performance Measurement and Verification Protocol. Building envelope properties were fixed and the values were taken from the national standards of Spain. This work validates solar heat gain coefficient as a primary variable in determining the annual solar heat gains in a building. Further work of developed model could result in building energy need quick evaluation tool in terms of solar heat gains for architects in building early stage as it has an advantage over detailed building simulation programs in terms of instant calculation and the limited need for predefined input data.

Radon Gas in the City of Alicante. High Risk of Low Indoor Air Quality in Poorly Ventilated Buildings.

In December 2019, Spain considered for the first time the presence of radon to the Technical Building Code (Basic Document HS 6: Radon Exposure Protection), although it only mentions minimum presences and the need for ventilation. This research shows that in buried structures or in places with little ventilation, even in soils with a low probability of granite, a high content of radon gas can be found. The city of Alicante has been used as a measurement location for different architectural sites; here, the level of 100 Bq/m3 is the first threshold where the gas must be monitored, and the level of 300 Bq/m3 is the maximum threshold above which corrective ventilation measures must be taken. The research conducted during the years 2015 and 2016 shows that it is necessary to account for also the areas considered to be “low presence of radon gas” to achieve healthy constructions. The renewal of air in the different places will be tested for the presence of radon, i.e., the greater the accumulation is, the less ventilation and the greater the risk of accumulation of radon gas. This study is located in the city of Alicante, where the seven civil constructions are located: two Civil War shelters, the Santa Barbara Castle, the Ereta Powder Keg, the Luceros-Marq and Serra Grossa railway tunnels and the Británica underground deposits. Radon gas is currently a concern for major health and medical agencies because it is considered to be a chemical element that is very harmful to people. The World Health Organization is one of the organisations that has the objective of studying and researching this element, to develop solutions. Radon gas is normally found in a gaseous state and is highly radioactive. It is present in many terrains and it is mostly found in those with granite; although the presence of this element is very low, there is always a minimum presence. In the past, in nongranite soils, the dose of radon was considered to be so low that it was insignificant. Therefore, in this research, the aim is to consider the high presence of radon gas in nongranite soils as long as the conditions for its accumulation are present.

Analysing the inequitable energy framework for the implementation of nearly zero energy buildings (nZEB) in Spain

Most countries from the European Union work towards a low-carbon horizon in the building sector. As for Spain, the last modification of the Spanish Building Technical Code in 2020 establishes that every building ensuring the fulfilment of the regulation will obtain the category of nearly zero energy building. However, the limit values of the thermal properties of envelopes only distinguish 6 variations according to the winter climate zone. For this reason, this study analyses the potential risk of the existence of energy inequalities due to the fulfilment of the regulation as regards energy efficiency in Spain. A total of 48,786 energy simulations were performed by taking the 8131 municipalities of the country into account, as well as the previous and current regulation. The results considered heating and cooling demands, cluster analyses, and their impact on population, showing that the improvement of thermal properties could guarantee buildings with a better energy performance for a greater number of inhabitants. There was, however, a limitation in the current climate classification, so a more detailed climate classification with new limit values is required. The results also showed the limitations of use of the thermal transmittance to reduce the cooling energy consumption. This study could be the starting point to establish new regulatory parameters to reduce energy consumption equitably, considering the importance of cooling consumption in future climate change scenarios.

Methodology for Quantifying the Energy Saving Potentials Combining Building Retrofitting, Solar Thermal Energy and Geothermal Resources

New technological, societal and legislative developments are necessary to support transitions to low-carbon energy systems. The building sector is responsible for almost 36% of the global final energy and 40% of CO2 emissions, so this sector has high potential to contribute to the expansion of positive energy districts. With this aim, a new digital Geographic Information System (GIS) platform has been developed to quantify the energy savings obtained through the implementation of refurbishment measures in residential buildings, including solar thermal collectors and geothermal technologies and assuming the postal district as the representative unit for the territory. Solar resources have been estimated from recently updated solar irradiation maps, whereas geothermal resources have been estimated from geological maps. Urbanistic data have been estimated from official cadastre databases. For representative buildings, the annual energy demand and savings are obtained and compared with reference buildings, both for heating and cooling. The GIS platform provides information on average results for each postal district, as well as estimates for buildings with particular parameters. The methodology has been applied to the Asturian region, an area of about 10,600 km2 on the Cantabrian coast of Spain, with complex orography and scattered population, qualified as a region in energy transition. High rehabilitation potentials have been achieved for buildings constructed before the implementation of the Spanish Technical Building Code of 2006, being higher for isolated houses than for collective buildings. Some examples of results are introduced in specific localities of different climatic zones.

TRANSFORMATION OF RESIDENTIAL HOUSINGS FROM THE REAL ESTATE BUBBLE INTO NEARLY-ZERO-ENERGY BUILDINGS: CASE STUDIES

Spanish residential buildings built during the real estate bubble (200-2009) complied with the Spanish Basic Building Standard on building thermal conditions NBE-CT-79. In 2006, the Basic Energy Saving Document of the Spanish Technical Building Code (CTE-DB-HE) came into effect. This code developed the Spanish Organic Law on Buildings 38/1999 and it was also much more restrictive. Recently, this regulatory framework has been updated by the Spanish Royal Decree 732/2019 on energy efficiency. This Royal Decree transposes European Directives 2010/31/EU, 2012/27/EU and 2018/844/EU on nearly-zero-energy consumption buildings (NZEB). In this paper, the energy, emissions and economic impact caused by this legislation change on a standard semi-detached house in the 153 cities of Andalusia is analyzed. In each location, the household’s original thermal behavior with the compliant with current legislation is compared. The calculations are performed with HULC energy simulation tool and the European PVGIS climate data, considering the most adverse orientations. The house adaptation involves a partial modification of the envelope, the inclusion of solar-thermal energy for the domestic hot water supply (DHW) and photovoltaic energy to reduce electricity consumption. Results show that European objectives are largely exceeded. Energy savings vary between 81% and 146%, emissions improve between 71% and 128% and the electricity and natural gas bill is reduced between 67% and 123%. Keywords: Spanish real estate bubble, energy efficiency, nearly-zero-energy building, thermal envelope, thermal insulation, solar-thermal energy, photovoltaic energy, technical building code, housing rehabilitation, Andalusia.

Adaptive setpoint temperatures to reduce the risk of energy poverty? A local case study in Seville

The reduction of energy poverty is among the main current challenges. One of the recent approaches is based on the reduction of the energy consumption through the climate adaptability of users. This research analyses the possibility of using adaptive setpoint temperatures to reduce the risk of energy poverty. A total of 6528 cases are considered in the south of Spain in 2015 and 2016 with actual data of temperature, hourly prices from the Voluntary Price for the Small Consumer, and the mean household incomes in both years. The energy consumption and expense are compared to both the static setpoints established by the Spanish Technical Building Code and the adaptive setpoints based on EN 16798-1:2019. In the annual calculation, by using both static and adaptive setpoints, the results show that the situation of energy poverty would only affect the family units belonging to the first decile of incomes. However, a monthly analysis identifies that the coldest or warmest months influence more deciles: for example, January 2015 affected until decile 8. The results also show that adaptive setpoints could reduce the risk of energy poverty in most cases, being more significant in Categories II and III from EN 16798-1:2019, in which this risk is reduced in all months of the year and in all deciles. This study aims to throw light on the use of HVAC systems according to the adaptation of users to reduce monthly the risk of energy poverty.

Blockchain adoptions in the maritime industry: a conceptual framework

ABSTRACT Blockchain technology has become one of the emerging technologies set to disrupt the maritime industry. Maritime companies are increasingly exploring to adopt blockchain to stay ahead of competition. However, studies on blockchain applications in the maritime sector have been scarce and most of them are confined to a specific sector like the maritime shipping sector. Therefore, this study is motivated to provide a thorough analysis of blockchain applications from the perspectives of different sectors in the industry. It also aims to develop a novel conceptual framework to provide a holistic view of blockchain adoption in the industry and guide future research. The implication analysis of blockchain adoption indicates that for industry organisations, a good understanding of blockchain and their own specific problems and requirements is key before adopting the technology. For government agencies, technical code for blockchain can be utilised to govern blockchain innovation with the same effects as legal code. Lastly, recommendations are provided to various maritime stakeholders to seize the emerging opportunities provided by blockchain and mitigate relevant risks.

Experimental Study on Shear Behavior of Reinforced Autoclaved Aerated Concrete Slab

Process two-points concentrate force load shearing trial for 6 ALC plates (Autoclaved aerated concrete reinforced plate), the article introduced the trial specimen structure, trial device and load scheme. This trial obtained the influence of the shear capacity of ALC plate like failure mode, load-deflection curve, stress (varying) distribution, steel types and shear span ratio. The research shown that: ①The reinforced ALC plate easily form the strong bending and weak shearing members, happen shear pressure failure when designed shear span ratio X=2.5, happen diagonal-tension failure, when designed shear span ratio X>5; ②If the oblique crack position close to the anchoring gusset or pass through anchoring section then maybe weaken the anchoring force and reduce the shearing strength of plate. Because of its brittle nature, anchorage failure must be avoid. Sufficient anchorage can theoretically be provided either by bond or by cross bars welded to the longitudinal reinforcement. ③For the calculation method of the shear bearing capacity of ALC without shear reinforcement with high strength longitudinal steel reinforcement, the technical code for the application of autoclaved aerated concrete in building in China is no longer applicable, EU standards calculated result are all less than the measured values, the method of international RILEM materials association is more suitable and the calculated value more close to the measured value.

Laboratory Tests on Hydraulic Lime Mortar Reinforced With Jute Fibres

Background:Considering the high seismic vulnerability of masonry buildings located in the Italian territory, the implementation of seismic retrofit programs is strongly needed.. With consideration for sustainable interventions, it is evident that the retrofit techniques to protect the historical heritage should be carried out with innovative green compound materials, such as mortars reinforced with natural fibres.Objective:In the current paper, laboratory tests on lime mortars strengthened with raw jute fibres have been performed.Methods:The workability of the fibre-reinforced mixture has been assessed through shaking table tests, and the mechanical resistances of standard specimens have been evaluated by bending and compression tests.Results:Considering the hygroscopic nature of jute, it has been identified that the optimal water/lime ratio and the maximum water percentage are absorbed by jute fibres. From the results, how the spreading of the mixture, which is indicative of the mortar consistency, changes with the water/lime ratio, has been evaluated. From bending tests, the effective behaviour of fibres, which provide a stitching effect of the failure crack in the investigated fibre-reinforced lime mortars, has been observed.Conclusion:Finally, the results of compression tests have shown that the examined fibre-reinforced mortars can be effectively used as building products according to the actual Italian technical code NTC 2018.

Kolob Runs on Domo: Mormon Secrets and Transhumanist Code

ABSTRACT Mormon religiosity is deeply marked both by a culture of secrecy and also by a culture that obliquely indexes secret religious material as a means of communication. This secrecy, though, can at times be an engine of disbelief, a process which has been exacerbated by the internet. Because of high levels of social integration in the community, Mormon disbelief can have high social costs. Some Mormons, however, have retained a ‘testimony’ by using the concept of transhumanism as a way to re-negotiate what ‘belief’ in Mormonism means. However, in part due to the very culture of secrecy that can fuel doubt, and also in part due to the technical codes that transhumanism as a community often relies on, this very shift can itself be difficult for Mormon non-transhumanists to discern.

Challenges in managing green building projects from the view of the contractors: An exploratory study in Vietnam

Success of green building projects is significantly dependent on the capacity of all stakeholders. In order to improve the success of such projects, this study seeks to gain a better and deeper understanding of the critical challenges facing the contractors in executing green building projects. The methodological framework used consists of a literature review and a questionnaire survey of green construction experts in Vietnam. The data collected from 163 expert responses was used to conduct the test of Kendall’s coefficient of concordance, Chi square tests, ANOVA and mean ranking analysis. The results indicate that the top five challenges facing the contractors in executing green building projects are “lack of legal regulations and technical codes, standards, guidelines on green building”, “more difficult to early establish a competent, integrated, multidisciplinary green project team”, “more difficult for comprehending the green specifications”, “more difficulty in the selection of competent subcontractors in providing green building services”, and “shortage of reliable green building methods, materials, technologies, and equipments in the market.” The findings bring out valuable implications for the government, the industry practitioners and stakeholders in improving the success of the green building projects in the future. Given the limited empirical studies on issues influencing the success of delivering green building projects, the present study also makes a contribution to the body of knowledge.

Study on calculation method of auxiliary materials for transmission tower

Comparing the provisions of domestic and foreign codes on the supporting force of auxiliary materials, the major domestic design institutes used design software, combined with the test results of the 220kV double-circuit linear tower (SZ801) true-type test, and concluded that compared with “Standard for design of steel structures”, “Design of latticed steel transmission structures “and the test results, the value of the internal force of the auxiliary materials of “Technical code for the design of tower and pole structures of overhead transmission line “is conservative. The value of the internal force of auxiliary materials supported by “Industry standards” only considers the influence of the main and inclined materials, and does not consider the effect of different equal distribution methods on the value.

Strategic analysis of China’s geothermal energy industry

China is an early user of geothermal energy, and its direct use ranks first in the world. Recent national strategies and policies have enabled China’s geothermal energy industry to enter a new era with important development opportunities. This paper investigates the strengths, weaknesses, opportunities, and threats (SWOT) to China’s geothermal energy industry from political, economic, social, and technological (PEST) perspectives. SWOT–PEST analysis indicates that the resources, market, and technological foundation exist for the large-scale development of China’s geothermal energy industry. However, it experiences constraints, such as unclear resource distributions, incomplete development of government regulations, incomplete implementation of national policies, unclear authority between governmental administrative systems, and lack of uniform technical standards and codes. Therefore, future development strategies have been proposed to provide technical support and policy tools for geothermal energy development. The recommendations to ensure its healthy and sustainable development include improving resource exploration, rationalizing administration systems, enhancing policy guidance and financial support, and cultivating geothermal talent.

Structural Responses of a Supertall Building Subjected to a Severe Typhoon at Landfall

Typhoon Mangkhut (1822) was one of the strongest tropical cyclones that ever impacted the south coast of China in past decades. During the passage of this typhoon, the structural health monitoring (SHM) system installed on a 303 m high building in this region worked effectively, and high-quality field measurements at nine height levels of the building were collected successfully, which provides a valuable opportunity to explore the dynamic properties of the building and the associated wind effects. In this study, the typhoon wind characteristics are presented first based on in-situ measurements at two sites. Acceleration responses of the building is then investigated, and the building’s serviceability is assessed against several comfort criteria. This study further focuses on the identification of modal parameters (i.e., natural frequency, damping ratio, and modal shape) via two methods: stochastic subspace identification (SSI) method and a method based on combined use of spectral analysis and random decrement technique (RDT). The good agreement between the two results demonstrates the effectiveness and the accuracy of the adopted methods. The obtained results are further compared with the stipulations in several technical codes as well as simulation results via finite element method to examine their performances in this real case. The amplitude dependence of natural frequencies and damping ratios of the studied building are also stressed.

Seismic fragility of existing RC buildings with corroded bars under earthquake sequences

Earthquakes are not isolated events and, typically, dominated by a larger-magnitude excitation (Mainshock – MS) and many smaller-magnitude motions (Aftershock – AS). Most often, such destructive events bring more damage than a single strong motion. Nowadays, many existing non-seismic designed RC structures are classified as either functional-obsolete or sub-standards. The seismic performance of these aged structures can be even more critical if some phenomena, such as corrosion, occur. The present study aimed at evaluating the seismic vulnerability of typical existing RC structures subjected to earthquake sequences and various levels of corrosion. A probabilistic approach via the fragility analysis, and three different seismic intensity measures (IM), was carried out. A four-story RC building was used as a testbed for Incremental Dynamic Analyses (IDA) via an advanced Finite Element approach. Twenty as-recorded natural motions were selected from international databases and inserted into the three-dimensional model. A new seismic intensity measure was provided and compared to the world-wide accepted peak ground acceleration (PGA) and spectral acceleration at the first natural period of the structure (Sa(T1)); the modified spectral acceleration intensity (MASI). The limit states of limited damage (LD) and severe damage (SD) were considered as capacity thresholds. The outcomes of this numerical investigation showed that multiple excitations and corrosion significantly affect the seismic vulnerability of the investigated building; MASI appeared to be the most effective intensity measure to assess the seismic fragility of corroded RC buildings; modern seismic-based technical codes are no longer conservative for such detrimental phenomena.

On the seismic fragility of pipe rack\u2014piping systems considering soil\u2013structure interaction

Piping systems constitute the most vulnerable component in down- and mid-stream facilities posing immediate threat to human lives, communities financial robustness and environment. Pipe racks present several mechanical and geometrical idiosyncrasies compared to common buildings and the seismic response is governed by the pipework layout. Important design requirements e.g. dynamic interaction between pipelines and supporting structure are commonly overlooked during pipe racks design process and uncertainties relevant to modelling of soil or seismic input are not quantified. In the present work, after reviewing the technical literature and codes, a 3D RC rack was used as a testbed and analysed as coupled and decoupled with a non-seismic code conforming piping system accounting for soil–structure interaction. Incremental dynamic analysis was adopted as an assessment methodology for deriving fragility curves considering ground motions in near- and far-field conditions. It was deduced that the modelling (boundary conditions of pipes) was the most considerable uncertainty since it increased the probability of collapse limit state of structural members from 0 to 59%. It was also demonstrated that soil deformability as well as source conditions altered considerably the dispersion of intensity measure conditional on engineering demand parameter of structural and nonstructural members. The results may be another indication that code provisions should be more normative regarding industrial pipe racks.

Evaluation of Formation of Plastic Hinge and Seismic Behavior of Steel Structures Due to Soil–Structure–Tunnel Interaction

The seismic design of the structures is carried out by technical regulations and codes in free-field conditions (regardless of underground cavities). With the availability of tunnels and the complex interaction between the tunnel and the aboveground structures, which may be contemplated wrongly, it could be dangerous for over ground buildings and structures. Consequently, the examination of the underground tunnels and their impact on the land surface and adjacent buildings seismic response seems to be significant. The present research focuses on formation of the plastic hinges in steel structures due to underground cavities and the soil–tunnel–structure interaction of underground structures. First, an existing model was verified by finite element method and the results were compared with a sample specimen. Thus, several effective parameters were considered and studied such as soil type, multi-story structures (4, 8 and 12 stories) and dynamic load type. Then the models were evaluated under real earthquake records. As a result, the seismic response of the structures and plastic conditions of plastic hinge conditions were obtained. The results indicate that the underground cavities have affected the formation of plastic hinges in the structure. They increased the input energy to the structure and had an impact on the total behavior of the structures. Also, the high-rise structures were much more vulnerable to underground tunnels. Therefore, the structures which are located above the underground cavities should be retrofitted and rehabilitated.