Base Of Wall Research Articles

ЧИСЛЕННОЕ МОДЕЛИРОВАНИЕ СВАЙНЫХ ФУНДАМЕНТОВ В РАСЧЕТНО-АНАЛИТИЧЕСКОМ КОМПЛЕКСЕ SCAD OFFICE

The article gives a comprehensive review of the main methods aimed at creating analytical and numerical models of slab-pile foundations in accordance with the present technical requirements using SCAD Office structural analysis software. Based on the example of a pile-and-slab foundation analysis, the authors compare the results which have been gained using analytical and numerical methods for two types of foundations, one of them has yield and the other one has rigid piling. Both foundations are ruggedized by basement walls. In order to determine the optimal analysis method for pile-and-slab foundation, three analytic methods of piling modeling are considered in accordance with SNiP 2.02.03-85 and SP 24.13330.2011. Besides, the authors have demonstrated the use of two numerical methods which are based only on the finite elements method for linear-elastic tasks solved using the widespread application sofware. The analytical modeling, which is regulated by standards, is carried out using the mathematical package SMath Studio. It is supposed that the complete analysis technology will use a standard mathematical package for import and export to and from the common data interchange format (DIF) in a structured view, which is acceptable for import and export in the SCAD system. A detailed description of the calculation technology is presented by the authors, thus indicating the applicability limits of these methods and recommendations for their use in static conditions. The demonstrated example testifies a fine precision of the considered methods. The research could be of great interest for designing engineers, university postgraduates and undergraduates.

Analysis of interaction of the soil temperature field and structures at the level of the basement of the building

The article describes an analysis of the effect of soil type on temperature field distribution at the level of family house basement. Regarding engineering calculations (heat loss calculation, designing and evaluating constructions), a simple and generally accepted method to determine the course of temperature field adjacent to basement walls is missing. The methods specified in European standards are, in terms of calculation of heat flows in soil, problematic. There is currently an insufficient number of measured values, which could be integrated in a simple calculation method. A certain option concerns continual measuring of temperatures in soil for buildings in situ. The article uses the measurements of soil temperatures in winter in pre-determined depths at the building parts in contact with soil. The measured data from a two-year period were integrated in the model on the basis of statistical evaluation. The main aim of the article is to generate an impulse to create unified outcomes of temperatures of certain soils for pre-selected depths, building structures, and parameters of indoor and outdoor environment.

November Light

November Light Ryan Brod (bio) In an abandoned woodlot, three of us stumble through the late September morning, adrenaline overtaking our weariness. Two bull moose spar on a distant ridge. We approach them cautiously, single file: Shawn, my father's neighbor, hunting partner, and recruited moose-caller; my dad, Steven, pushing seventy, faithful sub-permittee, struggling to keep up on bad knees; and me, the Bull-Only permit holder. Dad has postponed knee replacement surgery until mid-winter so he won't miss hunting season. Of the three of us, I am by far the least-accomplished hunter, which is at once comforting—the feeling one gets in the presence of experts—and, because of my historical bad luck, and general lack of experience, a little intimidating. We're more than three hundred miles north of my Portland apartment, on the eastern perimeter of the Allagash Wilderness. It's the second day of Maine's annual moose hunt. Shawn stops and crouches beside an old logging road, among tangled alders a few feet ahead of me. He's trying to blend in. In his mid-forties, Shawn appears younger, blonde hair winged from beneath his camouflage baseball cap. With both hands cupped over his nose and mouth, Shawn lets out a wailing call, opening his hands slightly [End Page 63] and lifting his head to mimic an eager cow. His call sounds to me like a whiny child. Dad crowds in behind me, looks frazzled after another night sleeping on the ground. "Those are both shooters," he whispers, his eyes on the moose as he fingers his leather gun sling. Two hundred yards away, in a clear-cut near the top of a ridgeline, the larger of the two sparring bulls turns to the sound of Shawn's call—apparently more intrigued by the prospect of female companionship than by fighting rivals—and lumbers toward us at full trot. You've got to be kidding me, I think, dropping to a knee and opening my shooting bipod with a loud, unintended clack. Shawn repositions behind me, my father beside him. I rest my rifle on the bipod and thumb off the safety. Through my scope, set to the fourth power of magnification, the moose's black body—crowned by magnificent, almond colored antlers—appears too large to be real. It slows to a walk, having cut the distance between us in half. The moose stops and laps its tongue against its wide brown nose. The breeze is behind us, and I'm nervous as hell. "I've got a shot," I whisper. My heart pounds. "Wait—still too far," Shawn says from over my shoulder. "Let it get closer." Then the bull steps from the logging road into the alder bushes, disappearing from my scope, from our view. I keep my scope fixed on the general area, waiting for the moose to step back out. Shawn makes another cow call. Nothing. I wait a few more seconds, then stand, collapse the bipod, and shoulder my rifle. "What happened?" Shawn asks, though none of us has the answer. Dad steps out from the brush, perplexed. "The wind must have busted us," he says. ________ On the basement wall of my childhood home, my father displayed the rack of every whitetail buck he'd ever shot. Many of the antlers were small: spikehorns, or four-pointers, screwed through small segments of skull to a horizontal wooden slab. "The antlers have been a way for [End Page 64] me to visually mark the passage of time and my own life," he told me once. Dad shot his first buck at age fourteen, on a hunting trip with his father, though he was alone when he killed the animal. "I kept thinking of how proud my father would be, and I dragged the deer a mile back to camp to meet him." It was a small buck, and his father couldn't hide his disappointment. "And so hunting has been a lifelong search for redemption, of sorts," he added. Later in his teen years, my father harvested a big ten-pointer, hunting alone this time. After it dropped, he walked to the buck and...

NUMERICAL SIMULATION OF RELATIVE HUMIDITY IN A MASONRY WALL APPLYING THREE DIFFERENT WATERPROOFING MEMBRANES

The analysis by numerical simulations can be applied to building materials subjected to different climatic conditions to envisage the influence of environmental factors in terms of drying time, water absorption and thermal performance of materials. Currently there is a wide variety of new building materials used for insulation, waterproofing and rehabilitation, each contributing in a specific way to constructions improvement during their service life. In time, every building is subjected to degradation due to the action of environmental factors. One of these is water due to its continuous acting under all forms of aggregation: vapour, liquid, solid, each having particular influence on the building s elements. The present paper highlights a numerical simulation of hygrothermal waterproofing characteristics for three different membranes applied on a brick masonry basement wall. The simulation was performed using WUFI2D 3.2 computer software. The information extracted from the analysis results made reference to the materials performance while subjected to moisture transfer processes.

Effect of Peripheral Wall Openings in Basement and Number of Basement Floors on the Base level of Braced Framed Tube System

For seismic design, the base is defined as the level at which the seismic ground motion is considered to be transferred on to the structure. Although there are many factors affecting the base level, for a typical building without a basement, the base is generally considered near the ground level. This study aims to examine the influence of both, peripheral wall openings in the basement and the number of basement floors, on the base level under near-field earthquakes, taking into account the effect of soil–structure interaction. To this end, five 2D metal-braced frame models with different number of floors and the soil around them were subjected to near-field earthquakes. The basement beams and columns were assumed to be buried within the peripheral basement wall. The results showed that where the opening was greater than 50%, the base level had to be considered one story lower than the ground level, thus, disregarding the effect of openings in high-rise structures could lead to non-conservative results. Moreover, it was concluded that in case the basement beams and columns were buried in the peripheral basement wall so as to provide sufficient stiffness, increasing the number of basement floors from 3 to 6 had little effect on the base level of the studied soil–structure system.

Primary energy benefits of cost-effective energy renovation of a district heated multi-family building under different energy supply systems

The European Union's Directive on energy performance of buildings emphasizes the need to take cost-effectiveness into account when measures are implemented for improved building energy efficiency. In this study, we investigate cost-effective energy renovation measures for a district heated building under different contexts, including varied locations, energy supply systems and economic scenarios. We determine the final and primary energy savings of cost-effective energy renovation packages for the building in the different contexts. The measures analysed include: improved insulation for attic floor, basement walls, and exterior walls; improved windows and doors; resource-efficient taps; heat recovery of exhaust ventilation air; energy-efficient household appliances and lighting. We consider three existing Swedish energy supply systems of varying district heat production scale and tariffs, and also plausible renewable-based energy supply systems. Our analysis calculates the final energy savings of the measures including the cost-effective renovation packages on hourly basis and links these to the different energy supply systems. The cost-effectiveness analysis is based on a double-stage optimization method, considering total and marginal investment costs of renovation measures as well as associated net present values of total and marginal cost savings. The results show that significant final and primary energy savings can be achieved when energy renovation measures are implemented for the building in the different contexts. This study shows that heat demand in existing Swedish building could be about halved while electricity use may be reduced considerably with cost-effective energy renovation measures. The economic viability of the renovation measures is sensitive to the economic regimes especially discount rates and energy price increase.

Pluvial, urban flood mechanisms and characteristics – Assessment based on insurance claims

Pluvial flooding is a problem in many cities and for city planning purpose the mechanisms behind pluvial flooding are of interest. Previous studies seldom use insurance claim data to analyse city scale characteristics that lead to flooding. In the present study, two long time series (∼20 years) of flood claims from property owners have been collected and analysed in detail to investigate the mechanisms and characteristics leading to urban flooding. The flood claim data come from the municipal water utility company and property owners with insurance that covers property loss from overland flooding, groundwater intrusion through basement walls and flooding from the drainage system. These data are used as a proxy for flood severity for several events in the Swedish city of Malmö. It is discussed which rainfall characteristics give most flooding and why some rainfall events do not lead to severe flooding, how city scale topography and sewerage system type influence spatial distribution of flood claims, and which impact high sea level has on flooding in Malmö. Three severe flood events are described in detail and compared with a number of smaller flood events. It was found that the main mechanisms and characteristics of flood extent and its spatial distribution in Malmö are intensity and spatial distribution of rainfall, distance to the main sewer system as well as overland flow paths, and type of drainage system, while high sea level has little impact on the flood extent. Finally, measures that could be taken to lower the flood risk in Malmö, and other cities with similar characteristics, are discussed.

Influence of Type of Frequency Weighting Function On VDV Analysis

Transport vibrations are the subject of many research, mostly their influence on structural elements of the building is investigated. However, nowadays, especially in the centres of large cities were apartments, residential buildings are closer to the transport vibration sources, an increasing attention is given to providing vibrational comfort to humans in buildings. Currently, in most countries, two main methods of evaluation are used: root mean squared method (RMS) and vibration dose value (VDV). In this article, VDV method is presented and the analysis of the weighting functions selection on value of VDV is made. Measurements required for the analysis were made in Krakow, on masonry, residential, two storey building located in the city centre. The building is subjected into two transport vibration sources: tram passages and vehicle passages on very close located road. Measurement points were located on the basement wall at ground level to control the excitation and in the middle of the floor on the highest storey (in the place where people percept vibration). The room chosen for measurements is located closest to the transport excitation sources. During the measurements, 25 vibration events were recorded and analysed. VDV values were calculated for three different weighting functions according to standard: ISO 2631-1, ISO 2631-2 and BS-6841. Differences in VDV values are shown, but also influence of the weighting function selection on result of evaluation is also presented. VDV analysis was performed not only for the individual vibration event but also all day and night vibration exposure were calculated using formulas contained in the annex to the standard BS-6841. It is demonstrated that, although there are differences in the values of VDV, an influence on all day and night exposure is no longer so significant.

Final energy savings and cost-effectiveness of deep energy renovation of a multi-storey residential building

In this study we present a method for analysis of cost-effectiveness of end-use energy efficiency measures and demonstrate its application for modelling a wide range of energy renovation measures for a typical 1970s multi-family building in Sweden. The method integrates energy balance and bottom-up economic calculations considering total and marginal investment costs of energy efficiency measures as well as net present value of total and marginal savings of the measures. The energy renovation measures explored include additional insulation to basement walls, exterior walls, and attic floor, improved new windows, efficient electric appliances and lighting, efficient water taps, glazed enclosed balcony systems, and exhaust air ventilation heat recovery systems. The measures are analysed first individually and then designed to form economic packages. Our results show that improved windows give the biggest single final energy savings while resource-efficient taps is the most cost-effective measure for the building. We find that the cost-effectiveness of the energy renovation measures is sensitive to real discount rates and energy price increases. Cost-optimal final heat savings varies between 34% and 51%, depending on the choice of real discount rate and energy price increase. The corresponding electricity savings varies between 35% and 43%. This study shows a method and the significance of various technical and economic-related parameters in achieving deep energy savings cost-efficiently.

The Implications of Climate Zones on the Cost-Optimal Level and Cost-Effectiveness of Building Envelope Energy Renovation and Space Heat Demand Reduction

The cost-optimal level of energy performance for buildings shall be identified according to the European directive of 2010. The Swedish building stock needs comprehensive knowledge and an overall strategy for the cost-optimal level of renovation. This paper studies the contribution of Swedish climate zones to the cost-optimal level of renovation on a multi-story residential building in Sweden from the building owner perspective. The building space heat demand is simulated for four Swedish climate zones. The net present profit (NPP) method is defined and used in this study in order to analyze the cost-optimal level and the cost-effective renovation of building envelope components (e.g., attic floor, basement walls, exterior walls and windows). The implication of different discount rates is studied, as well. The results show that the optimum renovation of the building envelope offers 51% more energy savings for space heating when the building is in a northern climate zone compared to a southern zone. The study suggests that different renovation strategies for the building stock renovation need to be identified, separately, for each climate zone. The NPP analysis identifies the minimum required investment and maximum achievable energy savings that are needed to have a cost-effective renovation. The broad range of studied climate zones provides the opportunity to apply the obtained results to other climate zones by either interpolation or extrapolation of NPPs for the buildings with similar characteristics.

Basement wall under earth pressure loading with low surcharge

AbstractThe structural verification of basement walls under earth pressure loading with low surcharge is often a difficult part of the everyday work of engineers. This situation is often encountered for basement walls under terrace doors, stair flights, masonry light wells etc., where the theoretically necessary surcharge loading is lacking. In this case, it is possible to transfer the acting forces from earth pressure with an arch model. One constructively possible measure to resist the resulting arch thrust is the provision of a sufficiently stiff reinforced concrete beam at the head of the basement wall. The article explains the verification of this method according to current standards.

Difficult Geotechnical Conditions Under the Palace Complex, Case Study from Cianowice, Near Krakow, Poland

The palace complex in Cianowice near Krakow (Lesser Poland, Poland) built around 1890, after 1945 ceased to function as a residential, so the whole building underwent successive devastation. Military activities, ad hoc repairs and long-term shortage of funds in Poland, led to the destruction of the magnificent assumptions. Since 2006. Palace remained completely unsecured and unattended. Performed in 2012-2015 modernization of the historic palace with the expansion of the basement (for residential building multigenerational) has become the occasion for a thorough diagnosis of the prevailing geotechnical conditions and the state of preservation of threads stone and brick walls and vaults chambers basement. Difficult ground conditions, water penetration, lack of insulation of horizontal and vertical has become one of the main causes of the destruction of the foundations and walls of basements. Moisture from the ground, rising damp in the walls (with dissolved salts in it), evaporate causing erosion of the walls. The result it led to the weakening of the structural and breakout layers of walls. The phenomenon has become particularly clear after the geotechnical surveys, excavations and complete discovery of the basement walls. The conducted works related to general technical renovation and restoration, included foundations (lining and insulation), walls, floors and roof. The assumption palace in Cianowice, through appropriate interference with the use of modern and introduction of a new substance, in any manner that emphasizes value and historical monument became possible to restore the important significance of the object and place.

Seismic Earth Pressures on Retaining Structures and Basement Walls in Cohesionless Soils

Observations of the performance of basement walls and retaining structures in recent earthquakes show that failures of basement or deep-excavation walls in earthquakes are rare even if the structures were not designed for the actual magnitude of the earthquake loading. For instance, no significant damage or failures of retaining structures occurred in the recent Wenchuan earthquake in China (2008) or in the subduction earthquakes in Chile (2010) and Japan (2011). To develop a better understanding of the distribution and magnitude of the seismic earth pressures on cantilever retaining structures, a series of centrifuge experiments were performed on model retaining and basement structures with medium dense cohesionless backfill. This paper provides a general overview of the research program and its results. Two sets of centrifuge-scale experiments were carried out on the centrifuge at the Center for Geotechnical Modeling at UC Davis. Three different types of prototype retaining structure were modeled in this research effort as follows: (1) a nondisplacing cross-braced (basement) structure with a stem stiffness of 5.92×1010 lb-in.2 per ft width (5.57×1005 kN-m2 per m width) and 1.04×1010 lb-in.2 per ft width (9.79×1004 kN-m2 per m width); (2) a nondisplacing U-shaped cantilever structure with a stem stiffness of 5.92 and 1.04×1010 lb-in.2 per ft width (9.79×1004 kN-m2 per m width); and (3) a free standing, cantilever retaining wall with a stem stiffness of 2.4×1010 lb-in.2 per ft width (2.26×1005 kN-m2 per m width). Overall, for the structures examined [i.e., wall heights in the range 6.1–9.15 m (20–30 ft)], the centrifuge data consistently show that the maximum dynamic earth pressure increases with depth and can be reasonably approximated by a triangular distribution. This suggests that the result of the dynamic earth pressure increment acts near 0.33H above the footing as opposed to 0.5–0.6 H recommended by most current design procedures. The current data also suggest that cantilever walls can resist ground accelerations up to 0.4 g if designed with an adequate static factor of safety.

Lithostratigraphic and sedimentary evolution of the Kom Ombo (Garara) sub-basin, southern Egypt

Southern Egypt is mostly covered by clastic sediments belonging to the Paleozoic and the Mesozoic. The Precambrian basement rocks bound the Etbai area to the east and Gabgaba area to the west. The basement extends further west forming dissected small and major exposures in southern Egypt, south of latitude 23° 30′ N but are covered by Cretaceous-Lower Tertiary sediments further north, the Western Limestone Plateau. The clastic sediments in southeast Egypt, on the western side of the basement rocks in-between latitudes 22° N and 24° 35′ N, built two sub-basins, Kom Ombo (Garara) sub-basin in the north and south Nile Valley sub-basin in the south. These are separated by a dissected basement wall. The two sub-basins have different lithostratigraphic successions, Paleozoic (Early to Late) in the south Nile Valley sub-basin whereas Late Paleozoic-Mesozoic-Tertairy in the Kom Ombo sub-basin. The platform clastic sediments within both sub-basins were possibly supplied from an easterly located Paleotethys extending to North Gondwana. The Oxfordian opening of the Indian Ocean associated with rise in sea level supplied more waters to the north and sediments by passed the filled southern Nile Valley sub-basin and reached the adjacent Kom Ombo sub-basin defining a depositional shift. On the other hand, during the Jurassic, Northern Egypt received Neotethys waters that filled deeper sub-basins (e.g., the Maghara sub-basin), hence the difference in lithology between Jurassic northern and southern sediments. Since the Jurassic, most of Egypt received Tethys waters. In the drilled wells studied, the younger top sediments surrounding the well sites are related to the Tethys geostratigraphy. The sub-basins in southern Egypt are controlled by N-S faults defining constant subsiding basins. The E-W Guinea–Nubia Lineament bounds the northern side of the Kom Ombo sub-basin, where it is closed by a northern basement arch.

Defender by Graham McNamee (review)

Reviewed by: Defender by Graham McNamee Kate Quealy-Gainer, Assistant Editor McNamee, Graham Defender. Lamb, 2016 [240p] Library ed. ISBN 978-0-553-49896-7 $20.99 Trade ed. ISBN 978-0-553-49895-0 $17.99 E-book ed. ISBN 978-0-553-49897-4 $10.99 Reviewed from galleys R Gr. 7-10 At six foot six, Tyne (Tiny) Greer casts an intimidating figure on the basketball court, but at heart she’s a softie who adores her supportive family and her goofy boyfriend, Stick. After an injury benches Tiny, she starts to help her dad with his superintendent duties in their building. While cleaning up the basement, she finds a decades-old body of a girl sealed up in the basement wall; when her dad he goes to check it out, he claims there’s nothing there. The body is indeed gone, but Tiny is certain of what she saw, and the prime suspect for moving the girl is now her beloved father. With the help of Stick’s sleuthing skills and few questions around the neighborhood, Tiny realizes her family’s past is hardly what she been told, and their secrets are bringing danger to both Tiny and Stick. Tiny’s happy existence turns oppressive and terrifying in the blink of an eye, and when she loses the picture of her father as a good and just man, it feels like another blow to her identity after losing basketball. Endearing Stick is determined to help Tiny, and while his CSI-like investigating is obviously convenient to the plot, it also seems to be just another quirk in a quirky kid. The loving jabs and smack talk that make up their interracial relationship (she’s white, he’s Latino) add a bit of levity to a dramatic situation. Red herrings will fake out even the most savvy reader, while the plot hustles along with plenty of dialogue and action. The premise and follow-through make this a solid win, especially for reluctant readers. [End Page 427] Copyright © 2016 The Board of Trustees of the University of Illinois

Lightweight masonry basement walls under out-of-plane loading

Extensive investigations were conducted in (Brameshuber et al., Standsicherheit horizontal belasteter Mauerwerkwande unter geringer Auflast, 2014) to analyse the load bearing and deformation behaviour especially of lightly loaded basement walls made of hollow clay units under out-of-plane shear load. Particular attention was paid to the bond between basement wall and the adjacent building members considering also the damp-proof courses. Therefore, an essential part of this work was the determination of the material laws of the bond at the bottom of the wall comprising the shear bond strength, the friction coefficient as well as the softening behaviour. For this purpose a test method was developed. The material laws were determined applying a two-dimensional numerical simulation of the shear tests by means of a best possible adjustment of the calculated curves to the test curves. Applying the material laws of the material components and the bond, two-dimensional numerical simulations of masonry walls under axial compression and out-of-plane shear load were performed. Simultaneously, experimental investigations with simplified horizontal load transfer were also conducted on floor-to-ceiling walls which served to calibrate the finite element (FE) model. Finally, a parameter study was performed with the calibrated FE model of the wall, selectively varying the distribution of the earth pressure as well as the value and eccentricity of the vertical load. From this study it becomes apparent that the earth pressure distribution exerts a decisive influence on the deformation and load bearing capacity of the basement wall.

Heavy rainfall: An underestimated environmental risk for buildings?

Although impacts of heavy rain on buildings in urban areas are often extensive, the public usually underestimates the negative consequences of that environmental risk compared e.g. to storm or hail events. However, the intensification of extreme weather events due to climate change as well as the rising physical vulnerability of assets are going to trigger the increase of impacts on the built environment. Heavy rain events are often highly localised that makes it difficult to estimate their probability and magnitude accurately. High intensity rain affects buildings both directly as well as indirectly.First, engineering surveys have already proven the broad variety and high physical vulnerability of building constructions that are directly and frequently affected by invading water during heavy rainfall events: flat roofs, roof terraces and balconies, connections between steep roofs and other building parts, soil-covered slabs of underground parking, soil-contacted basement walls and bottom plates as well as windows and external doors. It became evident that most damage is avoidable if exposed constructions become more resilient. Nevertheless, any adaptations require expertise on the demanding damage processes in order to explore deficiencies and to reduce physical vulnerability of building constructions exposed to heavy rainfall. In response to that challenge, the paper describes an engineering approach for the systematic classification of physical vulnerability criteria based on empirical research. A developed classification scheme allows the ex-ante examination of typical failure modes and the evaluation of negative consequences of heavy rainfall at individual building level. The topic is of high relevance, because the classification scheme may act as a capable tool for the prospective planning of adaptations towards more resilient buildings.Second, heavy rain may result in urban pluvial flooding due to sewer overflow that cause severe damage to buildings. A comprehensive study of the impacts and the consequences in Dresden (Germany), presented in the paper, revealed that the potential risks of flooding from sewers due to hydraulic overload can be estimated on building scale using the model approach IVART (Integrated Spatial Vulnerability and Risk Assessment Tool). Modelling results provide the basis to quantify the effectiveness and efficiency of flood resilience technologies.

PHC 파일을 이용한 영구벽체 융합 공법

This study was intended to suggest a new-concept construction method of permanent basement wall combined with earth retaining wall by using PHC piles to overcome the disadvantages of conventional CIP methods or the like which have been used just for earth retaining walls during field construction, and to determine its applicability. PHC piles are characterized by the reliable quality attributed to prefabrication (shop fabrication) as well as superior concrete strength and prestressing steel strength to that of CIP in the aspect of materials, and also higher bending moment than that of CIP in the aspect of structure.

Influence of sand density and retaining wall stiffness on three-dimensional responses of tunnel to basement excavation

Basement excavation inevitably causes stress changes in the ground, leading to soil movements that may affect the serviceability and safety of adjacent tunnels. Despite paying much attention to the basement–tunnel interaction, previous research has mainly focused on the influence of tunnel location in relation to the basement, tunnel stiffness, and excavation geometry. The effects of sand density and basement wall stiffness on nearby tunnels due to excavation, however, have so far been neglected. A series of three-dimensional centrifuge tests were thus carried out in this study to investigate these effects on the complex basement–tunnel interaction. Moreover, three-dimensional numerical analyses and a parametric study by adopting a hypoplastic sand model were conducted to improve the fundamental understanding of this complex problem, and calculation charts were developed as a design tool. When the basement was constructed directly above the existing tunnel, excavation-induced heave and strain were more sensitive to a change in soil density in the transverse direction than that in the longitudinal direction of the tunnel. Because a looser sand possesses smaller soil stiffness around the tunnel, the maximum tunnel elongation and transverse tensile strain increased by more than 20% as the relative sand density decreased by 25%. Moreover, the tensile strain induced along the longitudinal direction was insensitive to the stiffness of the retaining wall, but the tensile strain induced along the transverse direction was significantly reduced by a stiff wall. When the basement was constructed at the side of the existing tunnel, the use of a diaphragm wall reduced the maximum settlements and tensile strains induced in the tunnel by up to 22% and 58%, respectively, compared with the use of a sheet pile wall. Under the same soil density and wall stiffness, excavation-induced maximum movement and tensile strains in the tunnel located at a side of the basement were about 30% of the measured values in the tunnel located directly beneath the basement centre.

Cost-optimum analysis of building fabric renovation in a Swedish multi-story residential building

In this study, we analysed the cost-optimum level of building fabric elements renovation in a multi-story residential building. We calculated final energy use for space heating of the building considering a wide range of energy efficiency measures, for exterior walls, basement walls, attic floor and windows. Different extra insulation thicknesses for considered opaque elements and different U-values for new windows were used as energy efficiency measures. We calculated difference between the marginal saving of energy cost for space heating and the investment cost of implemented energy efficiency measures, in order to find the cost-optimum measure for each element. The implications of building lifespans, annual energy price increase and discount rate on the optimum measure were also analysed. The results of the analysis indicate that the contribution of energy efficiency measures to the final energy use reduces, significantly, by increasing the thickness of extra insulation and by reducing the U-value of new windows. We considered three scenarios of business as usual (BAU), intermediate and sustainability, considering different discount rates and energy price increase. The results of this analysis suggest that the sustainability scenario may offer, approximately, 100% increase in the optimum thickness of extra insulation compared to BAU scenario. However, the implication of different lifespans of 40, 50 or 60 years, on the optimum measure appears to be either negligible or very small, depending on the chosen scenario. We also calculated the corresponding U-value of the optimum measures in order to compare them with the current Swedish building code requirements and passive house criteria. The results indicate that all optimum measures meet the Swedish building code. None of the optimum measures, however, meet the passive house criteria in BAU scenario. This study suggests that the employed method of building renovation cost-optimum analyses can be also applied on new building construction to find the cost-optimum design from energy conservation point of view.