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We explore the process of modeling aeolian snow transport around buildings by proposing a set of similarity requirements on simulating a single snow fall event with drifting. The similarity criteria are used to guide our wind tunnel tests from the particle selection to the simulation set-up, including the determination of test wind speed, snowfall intensity and transported snow profile. In parallel, a specific field experiment on snow precipitation and drift around a 1-m prototype cube was achieved in Harbin to serve as the reference for the subsequent test validation. After reproducing a target wind and snow environment with a scale of 1:4 versus that of the prototype measurement, two verification tests were put forward using snow and substitution particles, which can mimic the effects of changing wind directions on the snow distribution. Herein, the wind tunnel and outside prototype results show good qualitative agreement in our limited range of length scales and particle properties. In future work, the range of scales and range of parameter values should be increased.
Borui Zhang; Qingwen Zhang; Feng Fan; Michael Lehning. Similarity conditions and cube model tests of snow drift and precipitation preferential deposition patterns. Journal of Wind Engineering and Industrial Aerodynamics 2021, 215, 104694 .
AMA StyleBorui Zhang, Qingwen Zhang, Feng Fan, Michael Lehning. Similarity conditions and cube model tests of snow drift and precipitation preferential deposition patterns. Journal of Wind Engineering and Industrial Aerodynamics. 2021; 215 ():104694.
Chicago/Turabian StyleBorui Zhang; Qingwen Zhang; Feng Fan; Michael Lehning. 2021. "Similarity conditions and cube model tests of snow drift and precipitation preferential deposition patterns." Journal of Wind Engineering and Industrial Aerodynamics 215, no. : 104694.
This study is motivated by the lack of a systematic way to reproduce vertical human walking loads with a damped bipedal inverted pendulum (DBIP). Measurements of vertical human walking loads for a sample of 16 Chinese test subjects were carried out with a non-commercial force plate on rigid surfaces, in which 2393 single-step forces were recorded and analyzed. The mean value of all the test subjects’ average step frequency of free walking is 1.73 Hz, which is lower than the reported data for other populations. Most test subjects are naturally slow walkers, whose first four harmonics dynamic load factors are found to be less than the well-reported data. Only the first harmonic dynamic load factor has a clear trend to increase with the step frequency. The best linear fitting curve is given in the form of y = a(x + b), in which a = 0.24 and b = −0.82. A previously developed DBIP, which can be described by four dimensionless parameters, i.e. the dimensionless energy input, leg stiffness, leg damping, and the attack angle, is then applied to reproduce these measured forces. The simulated force with a minimum root of the mean square error to the measured force is selected and calibrated to the required step frequency and amplitude, which usually has a smaller peak force compared with the measured data. The adopted model inputs are illustrated as functions of step frequencies. The DBIP is applicable for modelling part of the test subjects’ walking loads on rigid surfaces at different step frequencies.
Bintian Lin; Qingwen Zhang; Feng Fan; Shizhao Shen. Reproducing vertical human walking loads on rigid level surfaces with a damped bipedal inverted pendulum. Structures 2021, 33, 1789 -1801.
AMA StyleBintian Lin, Qingwen Zhang, Feng Fan, Shizhao Shen. Reproducing vertical human walking loads on rigid level surfaces with a damped bipedal inverted pendulum. Structures. 2021; 33 ():1789-1801.
Chicago/Turabian StyleBintian Lin; Qingwen Zhang; Feng Fan; Shizhao Shen. 2021. "Reproducing vertical human walking loads on rigid level surfaces with a damped bipedal inverted pendulum." Structures 33, no. : 1789-1801.
This paper presents a comprehensive comfort assessment method for indoor environmental quality in university open-plan offices (UOROs) in severe cold regions based on the combination weighting method. The questionnaires for the fuzzy analytic hierarchy process (FAHP) method were firstly collected from 405 experts to obtain the subjective weighting scheme of UOROs. Then, the field measurements of four environmental factors of 22 UOROs were conducted and the corresponding 1352 questionnaire surveys on the subjects’ comfort were collected. The relationships between four comfort factors and indoor environmental parameters were obtained from the field studies, and the objective weighting scheme was calculated using the entropy method (EM). Based on the game theory, the combination weighting scheme was given via integrating the results of the FAHP method and EM. The comprehensive comfort index for UOROs was finally provided by combining factor weights and fitting formulas, and the rationality and correctness of the method were demonstrated via experimental verification. Furthermore, the comparison of the weighting schemes between this study and other studies was discussed and the results revealed that the requirements of researchers for the sound environment were higher than normal office workers. The comprehensive comfort assessment method in this study can help designers and users to improve building performance by adjusting indoor environmental parameters and also make them better balance the relationship between human comfort and energy use.
Zheng Li; Qingwen Zhang; Feng Fan; Shizhao Shen. A comprehensive comfort assessment method for indoor environmental quality in university open-plan offices in severe cold regions. Building and Environment 2021, 197, 107845 .
AMA StyleZheng Li, Qingwen Zhang, Feng Fan, Shizhao Shen. A comprehensive comfort assessment method for indoor environmental quality in university open-plan offices in severe cold regions. Building and Environment. 2021; 197 ():107845.
Chicago/Turabian StyleZheng Li; Qingwen Zhang; Feng Fan; Shizhao Shen. 2021. "A comprehensive comfort assessment method for indoor environmental quality in university open-plan offices in severe cold regions." Building and Environment 197, no. : 107845.
Unbalanced snow distribution is one of the main reasons for the collapse of multi-span arch roofs due to excessive snow loads in the valley and leeward areas. The formation of uneven snowdrifts is closely related to the shape of the building as it seriously affects the turbulent structure and snow drifting process. This study aims to investigate the snowdrift characteristics of multi-span arch roofs based on a multiphase snowdrift approach. Firstly, the prediction accuracy of the flow field is tested to select a reasonable turbulence model. Then, the reliability of this multiphase approach is validated by comparing the results with a wind tunnel experiment of snowdrifts on a multi-span arch roof. The result preliminarily proves that this approach could well reproduce the unbalanced snowdrift on each span roof and at the trough. The snowdrift characteristics of multi-span arch roofs are investigated under different rise/span ratio and span number conditions based on the validated approach. The formation mechanism and characteristics of snowdrifts on different roofs are clarified by analysis. Finally, several typical distribution patterns are derived based on the statistical analysis of results. It is found that the middle-span roof bears a larger snow load than the roofs at both ends.
Guolong Zhang; Qingwen Zhang; Feng Fan; Shizhao Shen. Numerical simulations of snowdrift characteristics on multi-span arch roofs. Journal of Wind Engineering and Industrial Aerodynamics 2021, 212, 104593 .
AMA StyleGuolong Zhang, Qingwen Zhang, Feng Fan, Shizhao Shen. Numerical simulations of snowdrift characteristics on multi-span arch roofs. Journal of Wind Engineering and Industrial Aerodynamics. 2021; 212 ():104593.
Chicago/Turabian StyleGuolong Zhang; Qingwen Zhang; Feng Fan; Shizhao Shen. 2021. "Numerical simulations of snowdrift characteristics on multi-span arch roofs." Journal of Wind Engineering and Industrial Aerodynamics 212, no. : 104593.
The bipedal inverted pendulum with damping has been adopted to simulate human–structure interaction recently. However, the lack of analysis and verification has provided motivation for further investigation. Leg damping and energy compensation strategy are required for the bipedal inverted pendulum to regulate gait patterns on vibrating structures. In this paper, the Hunt–Crossley model is adopted to get zeros contact force at touch down, while energy compensation is achieved by adjusting the stiffness and rest length of the legs. The damped bipedal inverted pendulum can achieve stable periodic gait with a lower energy input and flatter attack angle so that more gaits are available, compared to the template, referred to as spring-load inverted pendulum. The measured and simulated vertical ground reaction force-time histories are in good agreement. In addition, the dynamic load factors are also within a reasonable range. Parametric analysis shows that the damped bipedal inverted pendulum can achieve stable gaits of 1.6 to 2.4 Hz with a reasonable first harmonic dynamic load factor, which covers the normal walking step frequency. The proposed model in this paper can be applied to human–structure interaction analysis.
Bintian Lin; Qingwen Zhang; Feng Fan; Shizhao Shen. A damped bipedal inverted pendulum for human–structure interaction analysis. Applied Mathematical Modelling 2020, 87, 606 -624.
AMA StyleBintian Lin, Qingwen Zhang, Feng Fan, Shizhao Shen. A damped bipedal inverted pendulum for human–structure interaction analysis. Applied Mathematical Modelling. 2020; 87 ():606-624.
Chicago/Turabian StyleBintian Lin; Qingwen Zhang; Feng Fan; Shizhao Shen. 2020. "A damped bipedal inverted pendulum for human–structure interaction analysis." Applied Mathematical Modelling 87, no. : 606-624.
Unbalanced snow loads on roofs have been a turbulent and significant problem for the building industry. Gables are one of the most common roof shapes, which are widely adopted as the roof shape for family residences, factories, ware houses, and garages. Series of experiments on an isolated gable-roof with or without scuttles and different roof pitches were done for the purpose of exploring the unbalanced patterns of snow loads. The model buildings made of wood have the same floor space, 2000 × 2000 mm but different roof pitches. A new open air snow–wind combined experimental facility was adopted in the experiments. The facility, which is like an open air wind tunnel with a snowfall simulator, can produce a stable wind field and snowfall environment for a specific duration. Artificial snow was used in the experiments, and particles properties were compared with natural snow previously proposed by the other authors. The experiment results indicated that the unbalanced snow loads were strongly connected with various wind velocities and roof pitches and a scuttle or other salient on the roof would bring an evident influence of patterns of snow distribution on the roofs.
Mengmeng Liu; Qingwen Zhang; Feng Fan; Shizhao Shen. Experimental investigation of unbalanced snow loads on isolated gable-roof with or without scuttle. Advances in Structural Engineering 2020, 23, 1922 -1933.
AMA StyleMengmeng Liu, Qingwen Zhang, Feng Fan, Shizhao Shen. Experimental investigation of unbalanced snow loads on isolated gable-roof with or without scuttle. Advances in Structural Engineering. 2020; 23 (9):1922-1933.
Chicago/Turabian StyleMengmeng Liu; Qingwen Zhang; Feng Fan; Shizhao Shen. 2020. "Experimental investigation of unbalanced snow loads on isolated gable-roof with or without scuttle." Advances in Structural Engineering 23, no. 9: 1922-1933.
Large grandstands provide areas for human activities and leisure pursuits. The degree of vibration comfort for people has an important effect on the functionality of grandstands. In this paper, the changes of the dynamic properties of the stand owing to different human postures are demonstrated. The comfort degree for human vibration in the large stand is also examined by full-scale measurements and questionnaire surveys. In addition, the analysis of the influence of different parameters on acceleration responses of the stand is presented via numerical simulation. Thereafter, it has been observed that ISO10137-2007 and BS6472 are more suitable than GB10070 and AISC-11 for evaluating vibration serviceability owing to crowd jumping loads during football matches in the large grandstand environment. Moreover, it has been observed that females and the staff are more likely to feel uncomfortable during matches, whilst students younger than 30 years old are the least sensitive group to vibrations of large stands. When the frequency of the jumping loads is close to the fundamental frequency of the stand or the synergy rate is high, the resonance is more likely to occur, which should be avoided by designers and users.
Zheng Li; Qingwen Zhang; Feng Fan; Shizhao Shen. Analysis of dynamic properties and vibration comfort of large-scale stands. Building Research & Information 2019, 48, 802 -816.
AMA StyleZheng Li, Qingwen Zhang, Feng Fan, Shizhao Shen. Analysis of dynamic properties and vibration comfort of large-scale stands. Building Research & Information. 2019; 48 (7):802-816.
Chicago/Turabian StyleZheng Li; Qingwen Zhang; Feng Fan; Shizhao Shen. 2019. "Analysis of dynamic properties and vibration comfort of large-scale stands." Building Research & Information 48, no. 7: 802-816.
In order to develop super long-span structures, the characteristics of suspension bridges are considered for use in suspended hybrid structures, initially considering a structure with a span of 800 m. The control parameters for the geometrical shape of the structure are given, and a structural model is established using ANSYS. The initial form of the main cable is studied and a feasible pylon scheme is designed. Static, stability and parameter analysis of the structure are conducted, and progressive collapse analysis after the breakage of the sling is undertaken. The results show that both wind loads and temperature have significant effects on the structure. There is not a destabilization problem exist in the structure and stiffness should be taken as the main consideration. The influence of geometrical parameters on the mechanical properties of the structure is studied, and variation rules for the parameters are summarized. The rise-span ratio of has a great influence on structural performance. When it changes from 1/10 to 1/5, the displacement decreases by 43%, the steel consumption reduces by 8.86%, and the stress decreases by about 10.69%. The possible progressive collapse of the structure following the failure of a single sling is examined. Using transient dynamic analysis. The time history curves of the responses to the process of the breakage of the sling are given. The work shows that it should be possible to develop suspended mega-latticed structures with spans of 800 m.
Qingwen Zhang; Zibin Zhao; Jianfeng Chen; Feng Fan; Shizhao Shen. On the static properties and stability of 800 m long-span mega-latticed suspension structures. Structures 2019, 23, 139 -151.
AMA StyleQingwen Zhang, Zibin Zhao, Jianfeng Chen, Feng Fan, Shizhao Shen. On the static properties and stability of 800 m long-span mega-latticed suspension structures. Structures. 2019; 23 ():139-151.
Chicago/Turabian StyleQingwen Zhang; Zibin Zhao; Jianfeng Chen; Feng Fan; Shizhao Shen. 2019. "On the static properties and stability of 800 m long-span mega-latticed suspension structures." Structures 23, no. : 139-151.
This paper presents a method for calculating uncomfortable rates of people subject to vertical floor vibrations, based on fuzzy reliability theory. In the first section, the membership function of the uncomfortable rate is determined based on fuzzy statistical experiments; the relationship between acceleration data and degrees of membership conforms to Stevens' power law. A formula for the uncomfortable rate is given using membership and lognormal distribution functions. The expression considers both the ambiguity of people's judgment and diverse perceived levels of different people to building vibrations. A design factor method based on the uncomfortable rate model is then given to optimize the design method. In the next section, parameters for the membership function are determined based on ISO 2631 and ISO 10137, and then the calculated curves for uncomfortable rates in buildings are derived. Curves for log-normal accumulation distributions are used to fit the original curves for uncomfortable rates. Changes in the coefficients of variations have little impact on the curves. Uncomfortable rates corresponding to different acceleration limits and functions for the design factor method of buildings are then obtained. In the last section, experimental verification of the method for calculating uncomfortable rates is performed via vibration measurements and questionnaire surveys. Thus, the rationality and correctness of the curves for uncomfortable rates are demonstrated.
Zheng Li; Qingwen Zhang; Feng Fan; Shizhao Shen. A method for calculating uncomfortable rates of people due to vertical floor vibrations using corresponding assessment values based on fuzzy reliability theory. Journal of Building Engineering 2019, 28, 101061 .
AMA StyleZheng Li, Qingwen Zhang, Feng Fan, Shizhao Shen. A method for calculating uncomfortable rates of people due to vertical floor vibrations using corresponding assessment values based on fuzzy reliability theory. Journal of Building Engineering. 2019; 28 ():101061.
Chicago/Turabian StyleZheng Li; Qingwen Zhang; Feng Fan; Shizhao Shen. 2019. "A method for calculating uncomfortable rates of people due to vertical floor vibrations using corresponding assessment values based on fuzzy reliability theory." Journal of Building Engineering 28, no. : 101061.
A considerable number of studies have been carried out for predicting snowdrifts on roofs over the years. However, few studies have focused on snowdrifts on complex long-span roofs, as the complex shape and fine structure pose significant challenges. In this study, to simplify the calculation requirements of snow load on such roofs, work was conducted to decompose the snowdrift on a complex roof into snowdrifts on several simple roofs. First, the snow–wind tunnel test similarity criteria were investigated based on a combined air–snow–wind experimental system. Thereafter, with reference to the validated experimental similarity criteria, a series of snow–wind tunnel tests were performed for snowdrifts on a complex long-span structure under the conditions of different inflow directions. Finally, based on empirical orthogonal function (EOF) analysis, the snowdrifts on the complex roof were decomposed into basic characteristic distribution modes, including snowdrifts caused by the local and overall roof forms. The snow distribution under a specific inflow direction could be derived from the weighted combination of the basic characteristic modes, based on the wind direction coefficients. Therefore, it is possible for the snow load on a complex roof to be estimated preliminarily based on the snow distributions on several simple roofs.
Guolong Zhang; Qingwen Zhang; Feng Fan; Shizhao Shen. Research on Snow Load Characteristics on a Complex Long-Span Roof Based on Snow–Wind Tunnel Tests. Applied Sciences 2019, 9, 4369 .
AMA StyleGuolong Zhang, Qingwen Zhang, Feng Fan, Shizhao Shen. Research on Snow Load Characteristics on a Complex Long-Span Roof Based on Snow–Wind Tunnel Tests. Applied Sciences. 2019; 9 (20):4369.
Chicago/Turabian StyleGuolong Zhang; Qingwen Zhang; Feng Fan; Shizhao Shen. 2019. "Research on Snow Load Characteristics on a Complex Long-Span Roof Based on Snow–Wind Tunnel Tests." Applied Sciences 9, no. 20: 4369.
Asymmetric triangulation is an interesting method combined with concentric pleating to obtain a 3D shape without stretching or tearing. There exists some geometric properties in the process of folding to help realize extension and contraction, which can be used in parametric modeling of different regular polygons. To facilitate design and modeling, adequate computational modeling methods are indispensable. This paper proposes a new mathematical idea and presents a feasible way to build the parameterized models in the digital environment of Rhinoceros, utilizing the Kangaroo plugin in Grasshopper. Designers can directly observe the models’ kinematic deployment and calculate the folding efficiency. It is concluded that the tendencies of folding efficiency in different regular polygons are not the same. To realize rigid folding, each polygon has a limited folding angle.
Qingwen Zhang; Danmin Yu; Xinye Li; Feng Fan; Yu; Li; Fan. Computational Modeling Methods for Deployable Structure Based on Alternatively Asymmetric Triangulation. Symmetry 2019, 11, 1278 .
AMA StyleQingwen Zhang, Danmin Yu, Xinye Li, Feng Fan, Yu, Li, Fan. Computational Modeling Methods for Deployable Structure Based on Alternatively Asymmetric Triangulation. Symmetry. 2019; 11 (10):1278.
Chicago/Turabian StyleQingwen Zhang; Danmin Yu; Xinye Li; Feng Fan; Yu; Li; Fan. 2019. "Computational Modeling Methods for Deployable Structure Based on Alternatively Asymmetric Triangulation." Symmetry 11, no. 10: 1278.
Unbalanced, or non-uniform, snow loads caused by snow drifting or sliding in cold regions with heavy snowfalls, can be a serious problem for the building industry. However, the methods for predicting snow distribution still need to be improved. Field observation is the most direct and reliable method to study snow distribution, but because the natural environment is uncontrollable and varies dramatically, sometimes conclusions may be confused under the influence of the many variables in the investigation. This paper proposes a snowing experiment approach using an outdoor snow–wind combined experiment facility for the study of snow distribution. The facility can produce a stable and controllable wind field and snowfall environment. Experiments which focused on snowdrift around a building were conducted during the winter to make an evaluation of the repeatability and reliability of the new approach. Finally, from the analysis of results, it was demonstrated that the experimental facility was stable and that the similarity criterion adopted for the snowing pattern was reliable. Especially, the minimum value of the friction speed ratio was suggested to ensure the test accuracy.
Mengmeng Liu; Qingwen Zhang; Feng Fan; Shizhao Shen. Modeling of the Snowdrift in Cold Regions: Introduction and Evaluation of a New Approach. Applied Sciences 2019, 9, 3393 .
AMA StyleMengmeng Liu, Qingwen Zhang, Feng Fan, Shizhao Shen. Modeling of the Snowdrift in Cold Regions: Introduction and Evaluation of a New Approach. Applied Sciences. 2019; 9 (16):3393.
Chicago/Turabian StyleMengmeng Liu; Qingwen Zhang; Feng Fan; Shizhao Shen. 2019. "Modeling of the Snowdrift in Cold Regions: Introduction and Evaluation of a New Approach." Applied Sciences 9, no. 16: 3393.
A general forming method for super-long span mega-latticed structures has been developed, based on the key parameters for five types of structure, together with a finite element model. The method combines the molding idea for universal spherical mega-latticed structures and the geometric topological relations of the improved traditional single-layer reticulated shell. The static and economic indexes of six kinds of 800 m span mega-latticed structures, with the same geometry, control parameters and loads, were calculated, and the force law for these structures under static load identified. Then structures suitable for spans of 1000 m and 1200 m were considered. The static performance and economic indexes showed that the mechanical and economic performance of the Geodesic type mega-latticed structure and the Three-dimensional grid type mega-latticed structure were excellent. In order to promote the engineering application of these structures, the influence of four key parameters on the performance of 1000 m structures was studied, and a reasonable range of indicative parameters obtained.
Qingwen Zhang; Yuan An; Zibin Zhao; Feng Fan; Shizhao Shen. Model selection for super-long span mega-latticed structures. Journal of Constructional Steel Research 2018, 154, 1 -13.
AMA StyleQingwen Zhang, Yuan An, Zibin Zhao, Feng Fan, Shizhao Shen. Model selection for super-long span mega-latticed structures. Journal of Constructional Steel Research. 2018; 154 ():1-13.
Chicago/Turabian StyleQingwen Zhang; Yuan An; Zibin Zhao; Feng Fan; Shizhao Shen. 2018. "Model selection for super-long span mega-latticed structures." Journal of Constructional Steel Research 154, no. : 1-13.