Existing Building Models Research Articles

Comparison in terms of Material Quantity Between Non-Seismic and Seismic Design for Selected Buildings in Malaysia

Almost all buildings in Malaysia were previously designed for non-seismic loading. As such, the need to consider seismic load poses challenges for the engineers and project owners. In order to enlighten the stakeholders on the effect of adopting seismic design, the impact on building material cost and quantities must be investigated in advance. Although many studies have been conducted, the use of hypothetical building models and not considering the actual soil factors in Malaysia may yield unrealistic results. As such, this study is conducted with the aim to evaluate the change in the material quantities of the main frame members using six existing building models subjected to peak ground acceleration of 0.16g and situated on soil type D. The analysis, design and taking-off were conducted with the aid of Tekla Structural Designer software. The results showed significant increase in terms of the material quantity required for the main frame members when seismic design was considered. The increase in the concrete volume and reinforcement tonnage was calculated to be in the range of 6.92% to 404.86% and 3.23% to 563.94%, respectively. The development of high base shear force, the amplification of the seismic force by the soft soil, and relatively stringent detailing in DCM were identified as the contributing factors. With a broader spectrum of results, the stakeholder can anticipate the increase in the material cost for adopting seismic design that can be useful for design submission and project cost estimation.

Seismic Evaluation of Retrofitting Technique Using Bracing Systems for Steel Multi-Story Building

A bracing system is the one of effective retrofitting methods for existing high buildings to support the lateral loads. Structural bracings increase the stiffness and stability of the building and the energy dissipation capacity. In this research, the numerical study of retrofitting a multi-story steel building near Imam Ali Holy Shrine in Najaf, Iraq has been conducted. The retrofitting mechanism includes a test of four different bracing systems such as X-bracing, V-bracing, Diagonal-bracing and IV-bracing located in the x and y-axis of the model. The seismic analysis using the elastic response spectrum method was performed for two types of earthquakes, weak and strong. The comparison among different parameters is discussed such as maximum lateral displacement, story drift ratio and base shear values. The seismic load was applied in two axes of the building model simultaneously and the results of the parameters in the x and y-axis were extracted. The results show that the retrofitting using four bracing system types increases the capacity of energy dissipation of the existing building model to seismic load by reducing the maximum lateral displacement in the x-axis by 55%, 44%, 41%, and 30% for X, IV, V and Diagonal-bracing, respectively. However, the X-bracing has a significant increase of the shear base value of the model by 39% and 49% in the x and y-axis, respectively, which means cost-effective compared with the other bracing types. Therefore, the IV-bracing type has an appropriate effect on the strength of the building against seismic load with reasonable cost-effectiveness.

The Energy Audit-Way of Energy Conservation

Energy audit is an important factor that enables the energy management programmer of any firm for controlling its energy costs. The Scenario of energy storage is compelling the adoption of energy conservation measure that describes the less energy for same level of activity. Energy audit basically controls the energy cost and increase the energy efficiency. Energy audit in business practice gaining continuous attention due to its vital role. This paper presents our motives of identifying the energy efficiency by practicing actual energy audit and finding how energy is being used in the facility. It also presents the ways of identifying the potential issues within building envelop thereby implementing the energy efficient technologies in lowering energy losses prominently with effective presentation of existing building model and its suggestive measures.

Simulation case study of stack pressure impact on thermal load in high-rise buildings

The reference building models in the EnergyPlus tool do not consider the stack effect. This is not an issue for small and low-rise buildings. However, this is significant in evaluating the heating and cooling load of high-rise buildings. This study evaluates and quantifies this stack effect in building energy simulation, EnergyPlus. The high-rise commercial building model in the EnergyPlus reference building set was used as a simulation test bed. The vertical multi-stories shaft zones were added inside the core zone in the existing building model. Then, the airflow network model was set in EnergyPlus so the internal airflow including the vertical and horizontal directions through the shaft zone as well as the core and perimeter zones were configured. The simulation model was calibrated against the actual pressure distribution between the core and perimeter zones in all floors of high-rise buildings from the literature. This model calibration was conducted manually by changing the discharge coefficient of the openings between thermal zones. The heating and cooling load of the proposed model were compared to the existing model which does not consider the vertical airflow through the shaft zones. The quantification with relative load mismatch was analyzed by floors and environment including the temperature difference between indoor and outdoor, and wind speed. Moreover, the impact of the air mixing and infiltration on the heating and cooling load was quantified. The result of this study reveals the significance of the stack effect in calculating the heating and cooling load.

Assessing Seismic Fragility of Low-Rise RC Buildings by means of Incremental Dynamic Analysis (IDA)

The modern era witnessed an urbanization and economic growth concentrated in urban areas. Despite an increase in welfare, this receives a greater threat when an earthquake occurs. This research aims to assess the structural risk of low to medium-rise reinforced concrete building structures, commonly built in developing countries. This research was carried out by performing an incremental dynamic analysis (IDA) od an existing building model. In this analysis, the structural model was given a set of dynamic earthquake loads which were increased in magnitude according to certain scale rules until the structure experienced nonlinear behavior and reached a near collapse condition. Five artificial accelerogram recordings were applied on the structure after matching with the spectral response of the target location of the structure. From the analysis, the IDA curves were obtained which describes the global dynamic behavior of the structure, namely displacement due to earthquake lateral loads. Then the damage limits were determined on the IDA curve based on the HAZUS criteria. Then the seismic risk was expressed by constructing a seismic fragility curve. This curve states the probability of exceeding certain damage limits due to variation in earthquake intensity during the service life of the structure.

Incremental constraint-based reasoning for estimating as-built electric line routing in buildings

This article addresses the augmentation of existing building models by a priori not observable structures such as electric installations. The aim is to unambiguously determine an electric network in an incremental manner with a minimum number of local measurements, e.g. using wire detectors, by suggesting the next measurement. Different reasoning strategies, e.g. utilizing graph-theoretical algorithms, have been presented and tested based on a hypothesis which is generated using Mixed Integer Linear Programming (MILP) while incorporating standards regarding the installation of electric wiring and findings from previous measurements. The presented method has been successfully applied on simulated and real-world buildings, it saves up to 80% of the necessary measurements compared to an exhaustive verification of the whole existing electric network, and paves the way for efficiently extending existing models, e.g. GIS models, with information on hidden utilities. This opens up new opportunities to model further infrastructures, e.g. water pipes, in future research.

Effectiveness and Efficiency of the Existing Building in Seismic Zone-III: A Case Study of Hotel Kaashi Building in Ujire

Abstract: Building irregularities are an important concern when they are subjected to strong earthquakes. In structures, an abrupt change in the vertical or plan configuration tends to weaken the stability. It is necessary to study how irregular structures respond to lateral loads in order to prevent failure and reduce the risk of hazards. In this case study, a G+3 storey building is modeled using the existing beam and column cross sections. In addition, models with reduced cross sectional areas of 5%, 10%, and 15% were developed and static linear analysis was performed using Etabs software in accordance with IS1893 (Part1):2016. The parameters considered in this study are storey displacement, storey drift, and base shear. The analytical results obtained are compared with those of the existing building model.

AUTOMATIC EXTRACTION OF FACADES AND WINDOWS FROM MLS POINT CLOUDS USING VOXELSPACE AND VISIBILITY ANALYSIS

Abstract. This contribution presents a method for extracting a 3D model of facades and windows from a point cloud. The point cloud is segmented based on a voxel octree, in which the facades are sought as planes. These can be used to filter out potential window points within the building, which are then analysed on their visibility by checking the occupancy grid of the voxel space. Here, methods of digital image processing are used for analysing both point clusters behind the facade and holes in the estimated facade planes as window candidates. Facades and windows are both simplified as rectangles. The test data set was gathered in a Mobile Laser Scanning campaign. While the segmentation fails in some cases, the extraction of facades and windows shows good results: 25 facades with 702 detected windows yield a detection rate of 86% with a false alarm rate of 13%. The reconstructed sizes of the windows differ from reference measurements in the range of centimetres to a few decimetres. These refined geometries can be used to enrich existing building models or for vehicle navigation without GNSS.

Modelling and calibration of infill frame-buildings, using ambient vibration tests and genetic algorithms

The presence of infill walls modifies the global structural response of frame buildings subjected to seismic loads. In evaluation studies, the stiffness of the structural elements and the mass of the building do not have great scattering; consequently, the variable to be analysed is the stiffness of the masonry. This investigation presents a process to determine a more realistic calibration of an existing building model using structural software and genetic algorithm programs made in Python 3 where the properties of the masonry were iterated to obtain modal periods similar to those obtained from ambient vibration tests. This programming can be freely downloaded and can be used in any optimisation case. The results highlighted the influence that non-structural masonry has over the overall behaviour of a building. It is also demonstrated that the use of a simplified macro model, with one spring that depicts the nonlinear performance of masonry, is an excellent option to address the limitations of commonly used software, as well as reducing processing time.

LiDAR point-cloud mapping of building façades for building energy performance simulation

Current processes that create Building Energy Performance Simulation (BEPS) models are time consuming and costly, primarily due to the extensive manual inputs required for model population. In particular, generation of geometric inputs for existing building models requires significant manual intervention due to the absence, or outdated nature of available data or digital measurements. Additionally, solutions based on Building Information Modelling (BIM) also require high quality and precise geometrically-based models, which are not typically available for existing buildings. As such, this work introduces a semi-automated BEPS input solution for existing building exteriors that can be integrated with other related technologies (such as BIM or CityGML) and deployed across an entire building stock. Within the overarching approach, a novel sub-process automatically transforms a point cloud obtained from a terrestrial laser scanner into a representation of a building's exterior facade geometry as input data for a BEPS engine. Semantic enrichment is performed manually. This novel solution extends two existing approaches: (1) an angle criterion in boundary detection and (2) a voxelisation representation to improve performance. The use of laser scanning data reduces temporal costs and improves input accuracy for BEPS model generation of existing buildings. The approach is tested herein on two example cases. Vertical and horizontal accuracies of 1% and 7% were generated, respectively, when compared against independently produced, measured drawings. The approach showed variation in accuracy of model generation, particularly for upper floors of the test case buildings. However, the energy impacts resulting from these variations represented less than 1% of the energy consumption for both cases.

Optimization and techno-economic assessment of rooftop photovoltaic system

The objective of this paper is to analyze the performance of the rooftop photovoltaic (PV) system, taking into account its shading impact on the rooftop surface and the eventual cooling load of the building. This paper tests three approaches of the rooftop PV system: zero tilt angle flat PV configuration; PV configuration with a monthly adjusted tilt angle; and PV configuration with a dual-axis sun tracking system. Each of the PV configurations is optimized to do the following: minimize the self-shading among the adjacent arrays; maximize the rooftop surface shading to curtail the cooling load; maximize the net energy yield; and minimize the net levelized cost of energy (LCOE) of the PV system. The existing building model is developed in SketchUp Pro. The model is simulated in an EnergyPlus environment to calculate the building's cooling energy consumption with different shading scenarios in various PV configurations. Various rooftop PV configurations are designed and simulated in a System Advisor Model (SAM) to analyze the effect of self-shading of the adjacent PV arrays on the PV performance. The optimal distance between the arrays (for maximum net energy yield and minimum net LCOE) is found to be 1.5 m. The net LCOE of the optimal scenario is 5.247 ¢/kW h and 4.112 ¢/kW h for monthly tilt and dual-axis tracking arrangements, respectively. The economic surplus of the optimized system is 0.422 ¢/kW h and 0.258 ¢/kW h for the monthly tilt and dual-axis tracking arrangements, respectively, as compared to the ground-mounted system.

Evaluation on Thermal Environment and Energy Consumption of a Demonstration Building in Ningqiang

The aim of this paper is to clarify the thermal performance and environment of a demonstration building in Ningqiang, China, utilizing building indoor temperature and energy consumption simulation program EnergyPlus. Compared with the existing building model, the energy saving rate of the demonstration building model is 42.42%, 6.92% higher than that of benchmark model, based on simulation analyses.

Matching Aerial Images to 3D Building Models Using Context-Based Geometric Hashing.

A city is a dynamic entity, which environment is continuously changing over time. Accordingly, its virtual city models also need to be regularly updated to support accurate model-based decisions for various applications, including urban planning, emergency response and autonomous navigation. A concept of continuous city modeling is to progressively reconstruct city models by accommodating their changes recognized in spatio-temporal domain, while preserving unchanged structures. A first critical step for continuous city modeling is to coherently register remotely sensed data taken at different epochs with existing building models. This paper presents a new model-to-image registration method using a context-based geometric hashing (CGH) method to align a single image with existing 3D building models. This model-to-image registration process consists of three steps: (1) feature extraction; (2) similarity measure; and matching, and (3) estimating exterior orientation parameters (EOPs) of a single image. For feature extraction, we propose two types of matching cues: edged corner features representing the saliency of building corner points with associated edges, and contextual relations among the edged corner features within an individual roof. A set of matched corners are found with given proximity measure through geometric hashing, and optimal matches are then finally determined by maximizing the matching cost encoding contextual similarity between matching candidates. Final matched corners are used for adjusting EOPs of the single airborne image by the least square method based on collinearity equations. The result shows that acceptable accuracy of EOPs of a single image can be achievable using the proposed registration approach as an alternative to a labor-intensive manual registration process.

Empirical modeling of the impacts of faults on water-cooled chiller power consumption for use in building simulation programs

Empirical models of four chiller faults that can be applied within existing building models to study overall impacts are developed in this paper. The faults include overcharging, excess oil, non-condensables in refrigerant and water-side condenser fouling. A single generalized model structured was developed for these faults that forces predicted fault impacts to be zero with no fault and increase with increasing fault level. The models were trained and tested using available laboratory data for a water-cooled centrifugal chiller where all four faults were artificially introduced. The fault model behavior was studied and then they were integrated in hospital models from DOE commercial reference building models (Deru et al., 2011) and simulations were performed in different climates. The simulation results showed maximum increases of building electricity consumption, electricity peak demand and water consumption of the hospitals due to faults of 4.7%, 7.8% and 1.8% respectively. The fault impacts were found to be more severe in hotter and more humid climates.

Seismic mitigation of an existing building by connecting to a base-isolated building with visco-elastic dampers

This study investigates the feasibility of retrofitting an existing building by connecting the existing building to a new building using connecting dampers. The new building is base-isolated and viscoelastic dampers are assigned as connecting dampers. Scaled models are tested under three different earthquake records using a shaking table. The existing building and the new building are 9 and 8 stories respectively. The existing building model shows more than 3% increase in damping ratio. The maximum dynamic responses and the root mean square responses of the existing building model to earthquakes are substantially reduced by at least 20% and 59% respectively. Further, numerical models are developed by conducting time-history analysis to predict the performance of the proposed seismic mitigation system. The predictions agree well with the test results. Numerical simulations are carried out to optimize the properties of connecting dampers and base isolators. It is demonstrated that more than 50% of the peak responses can be reduced by properly adjusting the properties of connecting dampers and base isolators.

QUALITY ASSESSMENT OF MAPPING BUILDING TEXTURES FROM INFRARED IMAGE SEQUENCES

Abstract. Generation and texturing of building models is a fast developing field of research. Several techniques have been developed to extract building geometry and textures from multiple images and image sequences. In this paper, these techniques are discussed and extended to automatically add new textures from infrared (IR) image sequences to existing building models. In contrast to existing work, geometry and textures are not generated together from the same dataset but the textures are extracted from the image sequence and matched to an existing geo-referenced 3D building model. The texture generation is divided in two main parts. The first part deals with the estimation and refinement of the exterior camera orientation. Feature points are extracted in the images and used as tie points in the sequence. A recorded exterior orientation of the camera s added to these homologous points and a bundle adjustment is performed starting on image pairs and combining the hole sequence. A given 3d model of the observed building is additionally added to introduce further constraint as ground control points in the bundle adjustment. The second part includes the extraction of textures from the images and the combination of textures from different images of the sequence. Using the reconstructed exterior camera orientation for every image of the sequence, the visible facades are projected into the image and texture is extracted. These textures normally contain only parts of the facade. The partial textures extracted from all images are combined to one facade texture. This texture is stored with a 3D reference to the corresponding facade. This allows searching for features in textures and localising those features in 3D space. It will be shown, that the proposed strategy allows texture extraction and mapping even for big building complexes with restricted viewing possibilities and for images with low optical resolution.

AUTOMATIC TEXTURE MAPPING WITH AN OMNIDIRECTIONAL CAMERA MOUNTED ON A VEHICLE TOWARDS LARGE SCALE 3D CITY MODELS

Abstract. Today high resolution panoramic images with competitive quality have been widely used for rendering in some commercial systems. However the potential applications such as mapping, augmented reality and modelling which need accurate orientation information are still poorly studied. Urban models can be quickly obtained from aerial images or LIDAR, however with limited quality or efficiency due to low resolution textures and manual texture mapping work flow. We combine an Extended Kalman Filter (EKF) with the traditional Structure from Motion (SFM) method without any prior information based on a general camera model which can handle various kinds of omnidirectional and other kind of single perspective image sequences even with unconnected or weakly connected frames. The orientation results is then applied to mapping the textures from panoramas to the existing building models obtained from aerial photogrammetry. It turns out to largely improve the quality of the models and the efficiency of the modelling procedure.

Samodejna koregistracija trirazsežnih modelov stavb z grafičnimi gradniki na podobah

The aim of this article is to investigate methods for the automatic extraction of the infrared (IR) textures for the roofs and facades of existing building models. We focus on the correction of the measured exterior orientation parameters of the IR camera mounted on a mobile platform. The developed method is based on point-to-point matching of the features extracted from IR images with a wire-frame building model. Firstly, the extraction of different feature types is studied on a sample IR image; Forstner and intersection points are chosen for a representation of the image features. Secondly, the three-dimensional (3D) building model is projected into each frame of the IR video sequence using orientation parameters; only coarse exterior orientation parameters are known. Then the automatic co-registration of a 3D building model projection into the image sequence with image features is carried out. The matching of a model and extracted features is applied iteratively, and exterior orientation parameters are adjusted with least square adjustment. The method is tested on a dataset of a dense urban area. Finally, an evaluation of the developed method is presented with five quality parameters, i.e. efficiency of the method, completeness and correctness of matching and extraction.

Multi-type change detection of building models by integrating spatial and spectral information

Detecting building changes followed by updates is preferable for efficient revisions to building models. Additionally, more change types can be detected with spatial information provided by building models for reducing land surveying work. Therefore, for efficient building of model revision and land surveys, this work applies a new multi-type change detection scheme with new light detection and ranging (LIDAR) point clouds, new aerial images and existing building models. By integrating the spatial information from LIDAR data and image-based spectral information, this work identifies changes to existing buildings and identifies newly built and changed buildings. To provide an initial value for further revisions, new building regions are generated from change detection results. Experimental results demonstrate that the proposed scheme has high accuracy for both change type determination and building region generation. To provide comprehensive observations, experimental results deemed unreliable are scrutinized.

An approach to distributed building modeling on the basis of versions and changes

Actors involved in the computer-supported design process work together towards a common goal – the design of a building. Current collaboration approaches often focus on versioned and distributed building models, which describe virtual building states on the basis of the object-oriented method. State changes (for example moving a wall or modifying its material) remain unconsidered and lead to inconsistency problems when exchanging, comparing and merging versioned building models. This paper presents a new modeling approach that combines existing state-oriented descriptions of a virtual building with additional change-oriented information by means of design steps denoted as modeling operations. A new language is defined for the formal description of modeling operations. These operations establish a standardized processing interface for existing building models, can represent design intents, enhance current models with change semantics and add to the consistency of these models. Moreover, this paper presents new concepts for intra-domain collaboration and model management that overcome current limitations when exchanging, comparing and merging versioned building models. The pilot implementation and some project scenarios in industry verify that current design processes can benefit in principle from combined state-oriented and change-oriented building information.