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Sloping topographies in urban areas are often under-utilised due to complex designs and difficult access, resulting in low construction productivity and high cost. Automated construction techniques are usually limited to flat sites or lab spaces. This research combines concepts for automated and prefabricated construction with hillside dwelling design. It proposes a strategy to integrate both aspects and to equally inform design process and design output. The aims are to turn hillside access and construction automation into design generators, improve productivity and use more affordable hillside sites.

Analysis of typologies for hillside housing and automated construction techniques is used to derive principles and parameters to inform a strategy and generative script for setting out, volumetric disposition and access and using the topography as a design-generator. The output from the generative script and tool can then form the basis of a high-density, low-rise dwelling development suited for serial, automation-assisted construction. The strategy is tested on a case study site.

The typological analysis helps devising strategies for integrating construction robotics and design criteria for hillside housing. The generative script illustrates how a strategy is implemented and used in a design tool able to absorb varying input data, including topographies. This generates innovative, site-specific design outcomes, suited for a process that adapts contemporary construction automation techniques and allows for more efficient use of hillside sites.

This research builds on construction automation methods and proposes novel combinations and adaptations for use on hillside sites. It demonstrates how robotics and generative tools can inform early design stages.

Three-dimensional printing of concrete (3DPC) has a potential for the rapid industrialization of the housing sector, with benefits of reduced construction time due to no formwork requirement, ease of construction of complex geometries, potential high construction quality and reduced waste. Required materials adaption for 3DPC is within reach, as concrete materials technology has reached the point where performance-based specification is possible by specialists. This paper aims to present an overview of the current status of 3DPC for construction, including existing printing methods and material properties required for robustness of 3DPC structures or structural elements.

This paper has presented an overview of three categories of 3DPC systems, namely, gantry, robotic and crane systems. Material compositions as well as fresh and hardened properties of mixes currently used for 3DPC have been elaborated.

This paper presents an overview of the state of the art of 3DPC systems and materials. Research needs, including reinforcement in the form of bars or fibres in the 3D printable cement-based materials, are also addressed.

The critical analysis of the 3D concrete printing system and materials described in this review paper is original.

Most of the 3D printing machines do not comply with the requirements of on-site, large-scale multi-story building construction. This paper aims to propose the conceptualization of a tower crane (TC)-based 3D printing controlled by artificial intelligence (AI) as the first step towards a large 3D printing development for multi-story buildings. It also aims to overcome the most important limitation of additive manufacturing in the construction industry (the build volume) by exploiting the most important machine used in the field: TCs. It assesses the technology feasibility by investigating the accuracy reached in the printing process.

The research is composed of three main steps: firstly, the TC-based 3D printing concept is defined by proposing an aero-pendulum extruder stabilized by propellers to control the trajectory during the extrusion process; secondly, an AI-based system is defined to control both the crane and the extruder toolpath by exploiting deep reinforcement learning (DRL) control approach; thirdly the proposed framework is validated by simulating the dynamical system and analysing its performance.

The TC-based 3D printer can be effectively used for additive manufacturing in the construction industry. Both the TC and its extruder can be properly controlled by an AI-based control system. The paper shows the effectiveness of the aero-pendulum extruder controlled by AI demonstrated by simulations and validation. The AI-based control system allows for reaching an acceptable tolerance with respect to the ideal trajectory compared with the system tolerance without stabilization.

In related literature, scientific investigations concerning the use of crane systems for 3D printing and AI-based systems for control are completely missing. To the best of the authors’ knowledge, the proposed research demonstrates for the first time the effectiveness of this technology conceptualized and controlled with an intelligent DRL agent.

The results provide the first step towards the development of a new additive manufacturing system for multi-storey constructions exploiting the TC-based 3D printing. The demonstration of the conceptualization feasibility and the control system opens up new possibilities to activate experimental research for companies and research centres.

This paper aims to report on the experiments with the Contour Crafting Automated Construction process using sulfur concrete as the choice of construction material.

Several experiments have been performed at centimeter and meter scales. A finite element analysis simulation model for the behavior of sulfur concrete-based structures has been developed. Experimental results were compared with the results of simulation.

Sulfur concrete has numerous terrestrial applications and is potentially an ideal construction material for planetary construction.

Experimental samples of sulfur concrete were fabricated using a novel mixer/extrusion system. The mechanism was proven to be durable and stable after more than 500 h of work.

The purpose of this paper is to present an introduction to geometric conformity principles for examining the geometric deviation between the desired (designed) and the fabricated surfaces which may be generated by a class of surface ruling fabrication processes such as flank milling, wire electrical discharge machining (WEDM), and contour crafting (CC).

In general, it is computationally challenging to calculate error approximation based on points. This paper proposes methods that efficiently calculate error approximation based on curve, surface area, and volume.

This paper derives the equations for calculating the ruled surface areas and the volume of 3D slices in 3D object models. One may use the difference of surface areas or volumes to determine the extent of the global conformity of the ruled surfaces. Additionally, local conformity analysis through calculating curve deviation has been introduced to improve the reliability of the global conformity analysis.

The research results apply only to fabrication processes that generate ruled surfaces. There are, however, numerous applications in which ruled surfaces are generated, such as WEDM, any numerical control machining which uses cylindrical or conical cutting bits, and CC.

The research results presented will be applicable to fabrication processes such as flank milling, WEDM, and CC.

All developments presented are original. Also, CC, which is a candidate process for the developments presented in the paper, has been invented and developed by the authors.

This paper presents the experimentation and modeling efforts at the University of Southern California, Los Angeles, to study the material flow patterns in the extrusion and deposition stages of the Contour Crafting (CC) process. A preliminary finite element analysis (FEA) was conducted for extrusion and deposition mechanisms of CC with ceramic materials (e.g. clay) as the fabrication material. Using the FEA simulations, certain basic understandings of the effect of extrusion orifice geometry on the performance of CC were derived. A square orifice was found to be aptly suited, both in terms of delivering excellent fusion between layers as well as creating the desired external surface profile. The experimental observations support these results.

This paper aims to investigate the extrudability (flow-ability and shape-stability) of concrete mixtures by using contour crafting (CC) as an automated construction process.

Several experiments have been performed for flow-ability and shape-stability of concrete mixtures. Experimental results were compared to understand significant factors and their interactions. After developing the empirical model for flow-ability, the model was validated.

The experimental investigation of varied combination of concrete components developed a mixture within constrains of the CC nozzle and improved the quality of the extruded part.

Several experimental samples were fabricated using CC, and the derived empirical model was validated after more than 700 h of work.

This paper presents research about the adaptation of Contour Crafting, a novel prototyping process, for two carefully chosen uncured ceramic materials. The details of the construction and operation of the fabrication machine, as well as procedures and results from our preliminary experimentation are concisely presented.

This paper aims to investigate the strength at interlayer of specimens fabricated using Contour Crafting (CC) to develop a concrete mixture for large-scale three-dimensional printing.

The collected data from several experiments were analyzed to understand significant factors and their interactions. After developing the empirical model, condition for maximum desirability was identified and the model was validated.

The experimental investigation of varied combination of concrete components introduced an empirical model which can predict the strength at interface. Moreover, an optimized mixture within constrains of the CC nozzle was developed and validated.

Several experimental samples were tested, and the derived empirical model was validated after more than 600 h of work.

Additive manufacturing of concrete (AMoC) is an emerging technology for constructing buildings. However, due to the nature of the concrete property and constructing buildings in layers, constraints and limitations are encountered while applying AMoC in architecture. This paper aims to analyze the constraints and limitations that may be encountered while using AMoC in architecture.

A descriptive research approach is used to conduct this study. First, basic notions of AMoC are introduced. Then, challenges of AMoC, including hardware, material property, control and design, are addressed. Finally, strategies that may be used to overcome the challenges are discussed.

Factors influencing the success of AMoC include hardware, material, control methods, manufacturing process and design. Considering these issues in the early design phase is crucial to achieving a successful computer-aided design (CAD)/computer-aided manufacturing (CAM) integration to bring CAD and CAM benefits into the architecture industry.

In three-dimensional (3D) printing, objects are constructed layer by layer. Printing results are thus affected by the additive method (such as toolpath) and material properties (such as tensile strength and slump). Although previous studies attempt to improve AMoC, most of them focus on the manufacturing process. However, a successful application of AMoC in architecture needs to consider the possible constraints and limitations of concrete 3D printing. So far, research on the potential challenges of applying AMoC in architecture from a building lifecycle perspective is still limited. The study results of this study could be used to improve design and construction while applying AMoC in architecture.