An experimental study on the lateral pressure of fresh concrete in formwork

Zhang, Wenxue; Huang, Jian; Li, Zengyin; Huang, Chun Lin

doi:10.1016/j.conbuildmat.2016.02.067

Cited by 13 publications

(6 citation statements)

References 10 publications

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“…The placement rate is one of the variables that exert greatest effect on fresh concrete lateral pressure. Zahng et al [6], in their empirical research with conventional concretes (compacted by vibration), obtained results that confirmed what is proposed by several calculation methods: placement rate directly affects the lateral pressure and the higher the values of this variable, the greater is the pressure exerted by the concrete. Santilli et al [7] observed in their study that placement rate and temperature are significant for estimating the fresh concrete lateral pressure, since these variables appear implicitly or explicitly in all the equations of the eight theories they studied.…”

Section: Introductionsupporting

confidence: 55%

“…The analysis of the prediction methods ACI 347 R-04, CIRIA R 108 and ABNT NBR 15696:2009 were conducted by comparing the fresh concrete lateral pressure estimated by these standards to empirical values presented by the authors: Arslan [14], Arslan et al [15], Maranhão [4], O'Janpa III [16] and Zhang et al [6]. In addition to the fresh concrete lateral pressure data measured experimentally, all variables of calculation, also measured by the authors, were collected.…”

Section: Analysis Of Theoretical Methods Of Calculating the Fresh Conmentioning

confidence: 99%

“…The placement rate values used were obtained from the ABRASFE [19] method. The concrete temperature used for the study was established on 25 °C (it was not measured in situ), presuming that on the experimental data presented by Arslan [14], Arslan et al [15], Maranhão [4], O'Janpa III [16] and Zhang et al [6], the concrete temperature did not surpassed 24 °C and on the prediction of fresh concrete lateral pressure, in accordance with NBR 15696 [9] methods it is not allowed to permit the temperature influence that exceeded 25 °C. Likewise, in accordance with the research executed by Gambale e Bittencourt [20], the temperature of the concrete made with CP II cements, does not exceed 25° C before 18 hours of concrete age.…”

Section: Maximum Pressure Supported By the Formworkmentioning

confidence: 99%

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Influence of the placement rate on the fresh concrete lateral pressure in the design of formworks

Sousa

Santos

Pereira

et al. 2018

Rev. IBRACON Estrut. Mater.

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ResumoThe fresh concrete lateral pressure generates a load that has great influence in the design of the formworks of columns, walls and lateral faces of the beams.Its prediction must be performed in such a way in order to approach precisely well over the rate values supported by the formworks, avoiding, therefore, the oversizing or undersizing of these temporary structures which represent up to 12% of the total cost of the construction. The calculation of the lateral pressure that fresh concrete exerts on the formworks involves several variables; one of them is the placement rate. The main objective of this work was to study the influence of the placement rate, in situ, on the lateral pressure of fresh concrete calculated from theoretical models presented by norms and international references. For this purpose, measurements of the placement rate were conducted on columns of five building work places at Goiânia city, Goiás, Brazil and it was calculated the maximum pressure supported by their respective formworks from the dimensions and spans between the supports of the components that constituted them. The obtained results indicate that the placement rate in the field observations reach 249 m/h, exceeding the values limited by the theoretical methods of calculation, and that the lateral pressure estimation produced from the placement rate measured in situ exceed the maximum values supported by the formworks up to 604 times. Thus, it was concluded that it is necessary to adjust equations to estimate the lateral pressure of fresh concrete at high rate of concrete placement, according to the current practices in the construction market.Keywords: lateral pressure, formworks, columns, placement rate.A pressão lateral do concreto fresco gera uma carga que possui grande influência no dimensionamento das fôrmas de pilares, paredes e faces laterais das vigas. Sua previsão deve ser realizada de modo que se aproxime bem dos valores suportados pelas fôrmas, evitando-se, assim, o superdimensionamento ou subdimensionamento dessas estruturas provisórias que representam até 12% do custo total da obra. O cálculo da pressão lateral que o concreto fresco exerce sobre as fôrmas envolve diversas variáveis, sendo uma delas a velocidade de concretagem. O principal objetivo deste trabalho foi estudar a influência da velocidade de concretagem sobre a pressão lateral do concreto fresco calculada a partir de modelos teóricos apresentados por normas e referências internacionais. Para isso, foram realizadas medições da velocidade de concretagem em pilares de cinco obras de Goiânia e calculadas as pressões máximas suportadas por suas respectivas fôrmas, a partir das dimensões e dos vãos entre os apoios dos elementos que as constituíam. Os resultados obtidos apontam que as velocidades de concretagem em campo chegam a 248,57 m/h, superando os valores limitados pelos métodos teóricos de cálculo, e que as estimativas da pressão realizadas a partir das velocidades medidas in loco ultrapassam os valores máximos suportados pelas fôrmas em ...

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Section: Introductionsupporting

confidence: 55%

Section: Analysis Of Theoretical Methods Of Calculating the Fresh Conmentioning

confidence: 99%

Section: Maximum Pressure Supported By the Formworkmentioning

confidence: 99%

See 1 more Smart Citation

Influence of the placement rate on the fresh concrete lateral pressure in the design of formworks

Sousa

Santos

Pereira

et al. 2018

Rev. IBRACON Estrut. Mater.

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“…For the construction of towering structures with turnover formwork on site, the risks involved in concrete placement operations cannot be ignored. During the pouring process, considering the influence of concrete slump, newly poured concrete lateral pressure [28], and concrete pouring speed under the influence of wind load [29] is important.…”

Section: Risk Indicators For Concrete Pouring Phasementioning

confidence: 99%

Safety Risk Assessment of Overturning Construction of Towering Structure Based on Cloud Matter–Element Coupled Model

Sang¹,

Han²,

Liu³

et al. 2023

Computer Modeling in Engineering &Amp; Sciences

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Rapid urbanization has led to a surge in the number of towering structures, and overturning is widely used because it can better accommodate the construction of shaped structures such as variable sections. The complexity of the construction process makes the construction risk have certain randomness, so this paper proposes a cloudbased coupled matter-element model to address the ambiguity and randomness in the safety risk assessment of overturning construction of towering structures. In the pretended model, the digital eigenvalues of the cloud model are used to replace the eigenvalues in the matter-element basic element, and calculate the cloud correlation of the risk assessment metrics through the correlation algorithm of the cloud model to build the computational model. Meanwhile, the improved hierarchical analysis method based on the cloud model is used to determine the weight of the index. The comprehensive evaluation scores of the evaluation event are then obtained through the weighted average method, and the safety risk level is determined accordingly. Through empirical analysis, (1) the improved hierarchical analysis method based on the cloud model can incorporate the data of multiple decisionmakers into the calculation formula to determine the weights, which makes the assessment results more credible; (2) the evaluation results of the cloud-based matter-element coupled model method are basically consistent with those of the other two commonly used methods, and the confidence factor is less than 0.05, indicating that the cloudbased physical element coupled model method is reasonable and practical for towering structure overturning;(3) the cloud-based coupled element model method, which confirms the reliability of risk level by performing Spearman correlation on comprehensive assessment scores, can provide more comprehensive information of instances compared with other methods, and more comprehensively reflects the fuzzy uncertainty relationship between assessment indexes, which makes the assessment results more realistic, scientific and reliable.

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“…Actually, there is an urgent need for monitoring the vibration depth at deeper depths, yet there is a lack of research and solutions in this area. Zhang et al [15] have investigated the impact of vibration depth on the lateral pressure against concrete formwork, introducing for the first time the concept of ultra-deep vibration: it occurs when the insertion depth of the vibrator exceeds the effective head height of the poured concrete. Ultra-deep vibration significantly increases the lateral pressure exerted on the formwork during vibration [16], necessitating strict control over the vibration depth.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Monitoring of Concrete Vibration Depth Based on RFID Scales

Quan,

Wang,

Liu

et al. 2024

Buildings

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The vibration of concrete is a typical concealed construction process, in which mature supervisory methods are lacking. The quality of vibration relies heavily on the subjective experience and sense of responsibility of the vibration operators. For the widely used hand-held concrete vibrators, existing methods for monitoring the quality of vibration primarily focus on the horizontal positioning of the vibrator. Due to the limited measurable range of vibration depth, these methods are inapplicable for monitoring the vibration depth during the vibration of deeper structures such as walls, columns, and large volumes of concrete. This paper makes the initial attempt to address the issue of monitoring concrete vibration depth, presenting a method that broadens the measurable range of depth in vibration monitoring. Inspired by the principles of optical and magnetic scales, this paper introduces a radio frequency identification (RFID) scales positioning system for the real-time monitoring of vibration depth. The proposed RFID scales vibration depth monitoring method theoretically has no upper limit on the measurable vibration depth, rendering it applicable to monitoring vibration depth of any extent. By comparing the positioning accuracy of different RFID scales hardware compositions, the optimal RFID scales hardware composition and the most effective RFID scales positioning algorithm were identified. The feasibility and accuracy of the vibration depth monitoring method based on RFID scales were validated through engineering field application. This method achieves centimeter-level accuracy in monitoring vibration depth, offers a tool for the precise control of vibration depth, and helps avoid potential quality issues in vibration.

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An experimental study on the lateral pressure of fresh concrete in formwork

Cited by 13 publications

References 10 publications

Influence of the placement rate on the fresh concrete lateral pressure in the design of formworks

Influence of the placement rate on the fresh concrete lateral pressure in the design of formworks

Safety Risk Assessment of Overturning Construction of Towering Structure Based on Cloud Matter–Element Coupled Model

Real-Time Monitoring of Concrete Vibration Depth Based on RFID Scales

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