Slab Thickness Research Articles

Evaluation of recycled gravel in the concrete mixture for the surface layer of rigid flooring

Paving with recycled aggregates has already been widely carried out in some countries where there is already consolidated knowledge on the subject. This work analyzes in the laboratory the physical and mechanical behavior aspects of recycled aggregate in concrete mixes for rigid pavements. After selective collection at a construction site, the waste undergoes a crushing process, subsequent to granulation and separation into fractions to be used again in the realization of a new mixture with 40 and 100% replacement of natural gravel for recycled with the addition of structural concrete fibers that decrease shrinkage and increase final strength. In the same mix, these mixtures were compared with a conventional mixture that obtained better performance and presented greater compressive strength. The study sought to analyze the technical feasibility of using recycled material, testing the thickness of several concrete slabs for application on the pavement. Thus, it is concluded that the analyzed recycled aggregate is of promising use in hard pavement coating, as it presents a compressive strength superior to 25 MPa.

Phases of the hard-plate lattice gas on a three-dimensional cubic lattice.

We study the phase diagram of a lattice gas of 2×2×1 hard plates on the three-dimensional cubic lattice. Each plate covers an elementary plaquette of the cubic lattice, with the constraint that a site can belong to utmost one plate. We focus on the isotropic system, with equal fugacities for the three orientations of plates. We show, using grand canonical Monte Carlo simulations, that the system undergoes two phase transitions when the density of plates is increased: the first from a disordered fluid phase to a layered phase, and the second from the layered phase to a sublattice-ordered phase. In the layered phase, the system breaks up into disjoint slabs of thickness two along one spontaneously chosen Cartesian direction, corresponding to a twofold (Z_{2}) symmetry breaking of translation symmetry along the layering direction. Plates with normals perpendicular to this layering direction are preferentially contained entirely within these slabs, while plates straddling two adjacent slabs have a lower density, thus breaking the symmetry between the three types of plates. We show that the slabs exhibit two-dimensional power-law columnar order even in the presence of a nonzero density of vacancies. In contrast, interslab correlations of the two-dimensional columnar order parameter decay exponentially with the separation between the slabs. In the sublattice-ordered phase, there is twofold symmetry breaking of lattice translation symmetry along all three Cartesian directions. We present numerical evidence that the disordered to layered transition is continuous and consistent with universality class of the three-dimensional O(3) model with cubic anisotropy, while the layered to sublattice transition is first-order in nature.

Performance Case Study of Concrete Bridge-Rail Post on Deck Overhang

Concrete post-and-beam bridge rails are a common bridge-rail type in the U.S. However, direct investigations of their performance on bridge-deck overhangs are rare, and current specifications do not clearly address this rail type or the design of decks supporting them. In this paper, the results of a performance case study of concrete bridge-rail posts on deck overhangs are presented. This study included (1) bogie testing of a MASH TL-4 concrete post on an instrumented deck, (2) development and calibration of a corresponding LS-DYNA model, and (3) use of the calibrated model to further describe system behavior, evaluate the effect of common design alternatives on performance, and corroborate the system performance from a full-scale crash test. The results of this study indicated that current design methods of the AASHTO LRFD Bridge Design Specifications (BDS) resulted in a significant underestimation of lateral capacity, partially because their neglect of inertial resistance. In the bogie test of the concrete post, over 40% of the peak lateral resistance of the post was attributed to inertial effects. Similarly, the calibrated LS-DYNA model indicated that the full-scale system could withstand a simplified single-unit truck (SUT) loading consisting of a 150 kip pulse load while only sustaining minor damage, despite having a BDS-predicted capacity of 73 kips. Additional findings included a characterization of deck demands, performance effects of design alternatives, such as edge distance and slab thickness, and the influence of using straight versus hooked transverse deck bars.

Validation of a detonation product equation of state for an insensitive high explosive via slab geometry expansion tests

Slab expansion (SLABEX) tests are conducted to validate a process for calibrating the detonation products equation of state (EOS) of a high explosive (HE). The SLABEX tests use rectangular slabs of PBX 9502, a polymer-bonded HE formulation consisting of 95 wt.% 1,3,5-triamino-2,4,6-trinitrobenzene bound with Kel F-800, a co-polymer of chlorotrifluoroethylene and vinylidene-fluoride. Three PBX 9502 slab thicknesses are examined, each confined symmetrically by two rectangular copper (Cu) plates approximately one-tenth the thickness of the HE slab. For the duration of each experiment, the detonation flow along the central axis of the PBX 9502 slab remains two-dimensional. The lateral flow velocity component of the outer surfaces of the expanding Cu plates is measured, along with the steady axial detonation speed along the central axis of the SLABEX. Hydrodynamic simulations of the Cu plate expansion in the SLABEX geometry, driven by the energy stored in the detonation products by the detonation combustion event, are conducted using a Jones–Wilkins–Lee EOS for the detonation products. This EOS form was recently parameterized for PBX 9502 in the cylinder expansion test geometry using a newly developed calibration technique [Voelkel et al., Combust. Flame 246, 112373 (2022)]. Good agreement between the experiment and prediction is found in each SLABEX test, demonstrating that the detonation product EOS calibration technique produces EOSs that are predictive when applied to other geometries.

In situ experimental study of vibration reduction using thick concrete slabs with natural and cement-improved subgrade

Thickening the foundation slab and improving the subgrade soil using geo-techniques are effective measures for controlling unwanted vibrations at high-tech facilities. In this study, the vibration-reduction performance of 1-m-thick concrete slabs with natural and cement-improved subgrades was investigated based on in situ frequency sweep tests. One 1-m-thick concrete slab rested on 1-m-thick compacted sandy gravel backfill atop an undisturbed subgrade was constructed on the north side of the experimental site, and another identical concrete slab rested on 1-m-thick compacted sandy gravel backfill atop a cement-improved subgrade was constructed on the south side. The vibration-reduction effect was evaluated by comparing the free-field ground vibrations and surface vibrations of the two slabs at three pairs of evaluation locations. In terms of peak velocity, the 1-m-thick concrete slab with the natural subgrade exhibited a slight vibration amplification effect at low frequencies and a significant reduction effect at middle and high frequencies; the 1-m-thick concrete slab with the cement-improved subgrade exhibited a continuous vibration reduction action at all frequencies. In terms of RMS velocity, the vibration-reduction performance of the 1-m-thick concrete slab with the cement-improved subgrade was better than that with the natural subgrade. The results demonstrated that the vibration-reduction effect of the thick concrete slab was significant and could be increased by improving the subgrade using the cement grouting method.

Blast resistance of ECC and composite slabs subjected to near-field explosion

Due to the unfavorable blast resistance of reinforced concrete (RC) slabs, particularly with the frequent occurrence of penetration and spalling damage, engineered cementitious composite (ECC) provided a promising alternative for enhanced blast resistance through its direct application as a building material or by reinforcing existing RC slabs due to its excellent tensile ductility and toughness. In the present study, the blast resistance of the RC slab, the ECC slab, and the composite slab (RC slab reinforced by ECC layer) was investigated and compared through experimental and numerical approaches. Firstly, the material properties of the ECC were acquired through the quasi-static compressive test, as well as quasi-static and dynamic tensile tests, which felicitated the parameter calibration in the K&C model for ECC. Then the numerical models of the RC slab, the ECC slab, and the RC/ECC composite slab were established and validated with the blast test results. The test and numerical results showed that the ECC and composite slabs exhibited superior anti-blast performance in terms of failure mode, damage extent, and load mitigation compared to the RC slab. Owing to the remarkable ductility and toughness, the ECC and composite slabs could greatly reduce the possibility and severity of penetration and spalling damage. Furthermore, five significant parameters impacting the blast resistance of ECC and composite slabs were summarized through dimensional analysis including the tensile strength of ECC σt, the total explosive energy Q, the standoff distance R, the slab thickness H, and the slab span L. Then a dimensionless number was proposed to determine the failure mode and predict the residual deflection at the center of the ECC and composite slabs. The results could serve as a reference for the design of ECC and composite slabs to resist blast loading in the field of structural protection.

Damage behavior of concrete members subjected to underwater contact explosion

In order to investigate the damage mechanism of dams subjected to underwater contact explosion, firstly, an experimental program was conducted with six concrete slabs and two explosive quantities. The test results showed that the diameter and depth of the crater on the front and back surface of the concrete slab increased with increasing explosive quantity with radial and circular cracks generated. Three different concrete material models were tested and it was found the CDP model was most suitable in simulating concrete subjected to underwater explosion. The calibrated models were used to conduct parametric studies to study the effect of explosive quantity, slab thickness, and transferring medium (water or air). Numerical analysis results showed that the diameter and depth of the crater on both the front and back surface of the concrete slab decreased with increasing slab thickness and decreasing explosive quantity. In addition, the damage caused by the air contact explosion was smaller and more concentrated in the detonation center compared with underwater contact explosion. Finally, a gravity dam and an arch dam were modeled to study the effect of detonation depth and water level on the damage distribution pattern of the dams. Based on the results, recommendations were provided for the anti-explosion protection design of hydraulic structures.

Structural design of hybrid steel-timber buildings for lower production stage embodied carbon emissions

Using cross laminated timber (CLT) floor panels in combination with steel framing has been identified as a promising new structural configuration that can reduce the embodied greenhouse gas emissions of buildings. This project evaluated efficient structural design of hybrid steel-timber floor sections for a wide range of design parameters to determine the reductions in global warming potential possible relative to a conventional steel-concrete cross section. Each of the structural designs was checked for strength limit states, deflection, and minimum fire rating of either unrated, 1-h, or 2-h for a range of deck spans between 2.3 m and 4.6 m and beam spans between 5.5 m and 13.5 m. For an unrated floor assembly there is little global warming potential benefit to use steel-timber floors if a topping slab is included on top of the CLT slab. Whereas, using steel-timber configurations without a topping slab result in the largest global warming potential reductions. For the 1-h and 2-h ratings, even steel-timber configurations with a 64 mm thick topping slab had up to 20% reduction in global warming potential compared to the steel-concrete alternative. Additionally, several considerations that can drastically affect the global warming potential results were discussed. The results from this project demonstrate the best practices for structural design of hybrid steel-timber buildings to reduce global warming potential of the superstructure frame by between 5% and 35% relative to conventional steel and concrete construction.

Improvement strategies of cement concrete pavement structure on part-fill and part-cut subgrade

ABSTRACT The unavoidable transverse non-uniformity of settlement and moduli for part-fill and part-cut subgrade may have some critical impact on concrete pavement structures, hence, some structural optimisations of pavement based on the working conditions of subgrade are essential. In this study, on account of the practical working conditions of part-fill and part-cut subgrade, a finite element model of concrete pavement structure on part-fill and part-cut subgrade developed previously was conducted to analyse the effects of slab thickness, slab concrete modulus of rupture, tie bar diameter and tie bar spacing. Furthermore, improvement methods and strategies were analysed and proposed for the four parameters respectively with fatigue cracking design life under loading as the target and maximum stress at the bottom of slab as the criterion. The results verified the feasibility of incorporating non-uniformity of modulus and settlement into the design phase of concrete pavements on part-fill and part-cut subgrade. Additionally, concrete pavement parameter optimisation priority should be given to concrete modulus of rupture, slab thickness, followed by tie bar diameter and spacing. It can provide a useful reference for designing concrete pavement structures on part-fill and part-cut subgrade.

Multi-point scattering measurements for effective property extraction from metamaterials with skin effects

Scattering experiments can be leveraged to extract the effective properties of a heterogeneous metamaterial slab based on multi-point measurements in surrounding media. In this technique, two measurements are made in the ambient media on each side of a finite thickness micro-structured slab to decompose incoming and outgoing waves. The method is applied to an example with locally resonant micro-structured inclusions while paying close attention to parameters that influence the extracted material parameters. It is observed that the extracted overall parameters converge to limiting values when the number of unit cells across the slab thickness or ambient media modulus are increased. Dependence of extracted material parameters on the number of cells through thickness or ambient media properties are attributed to the different response of boundary (skin) and interior cells. A method is presented which represents a finite array with different effective properties for the skin regions vs. the interior regions with great success in reproducing the scattering for different slab thicknesses, and through which the interior regions properties become independent of ambient media properties. In stop bands with lower material loss, challenges arise that are associated with extremely small transmission. The assumption of continuity in transmission phase is enforceable to remove phase ambiguity, although in certain cases (associated with nearly lossless specimens) this assumption appears to fail. In such cases, interference from coupled shear modes may lead to apparent higher longitudinal transmission within the stop band. This work provides a proof of concept for the development of an experimental methodology capable of extracting the effective properties and dispersion behavior of heterogeneous mechanical metamaterials without any knowledge of the internal fields.

Flexural behavior of reinforced concrete slabs containing recycled glass powder and steel fibers

Because of the massive environmentally unsustainable output from industrialization, concrete can benefit from using glass powder (GP) as a cement replacement to achieve sustainability. This research addresses the experimental results for seven reinforced concrete (RC) slabs containing recycled GP and steel fibers (SF) under flexure. The experimental variables are the replacement ratios of GP by cement weight (0 %, 10 %, and 20 %), the addition of SF (0 %, 0.5 %, and 1 %), slab thickness (100 mm and 120 mm), and the ratio of longitudinal reinforcement (0.61 % and 0.86 %). The load–deflection curves, load-steel strain relationships, stiffness, ductility, and toughness are plotted and calculated. Test results showed that the compressive and splitting strengths of concrete mixes containing 10 % GP at 28 days increased by 4.7 % and 1.7 %, respectively, compared to the conventional concrete. For the case of the 20 % addition of GP, the compressive and splitting strengths decreased by 10.7 % and 5.9 %, respectively compared to the conventional concrete. Experimental results indicated that utilizing GP as a substitute for cement by 10 % and 20 % shows an acceptable performance of RC slabs and 10 % GP is the optimum replacement ratio that is suitable for use in concrete mixes. Slabs containing 10 % GP indicated an increase in the failure loads by 8.8 % and that has 20 % GP indicated insignificant reductions in the failure and crack loads by 14.7 % and 5.9 % respectively. The addition of SF to concrete containing GP improved the performance, toughness, and stiffness of RC slabs. Finally, a comparison between the results of the experiment and the provisions of different design codes was performed and a good agreement has been reported. The average value between the predicted and experimental load capacities was 0.99 with a standard deviation of 0.10.

Kimberlite eruptions driven by slab flux and subduction angle

Kimberlites are sourced from thermochemical upwellings which can transport diamonds to the surface of the crust. The majority of kimberlites preserved at the Earth’s surface erupted between 250 and 50 million years ago, and have been attributed to changes in plate velocity or mantle plumes. However, these mechanisms fail to explain the presence of strong subduction signatures observed in some Cretaceous kimberlites. This raises the question whether there is a subduction process that unifies our understanding of the timing of kimberlite eruptions. We develop a novel formulation for calculating subduction angle based on trench migration, convergence rate, slab thickness and density to connect the influx of slab material into the mantle with the timing of kimberlite eruptions. We find that subduction angles combined with peaks in slab flux predict pulses of kimberlite eruptions. High rates of subducting slab material trigger mantle return flow that stimulates fertile reservoirs in the mantle. These convective instabilities transport slab-influenced melt to the surface at a distance inbound from the trench corresponding to the subduction angle. Our deep-time slab dip formulation has numerous potential applications including modelling the deep carbon and water cycles, and an improved understanding of subduction-related mineral deposits.

Critical collapse deformation of 3-D steel frame with composite floor system

Determination of the CCD (critical collapse deformation) for frame structures is crucial to calculate their final collapse resistance due to a column loss. This paper studies the CCD of 3-D (three-dimensional) steel frame structure in an interior column loss. The work presented in this paper is an extension of previous work by authors on two-dimensional (2-D) steel frame, by further introducing the effects of concrete floor slab. The fracture of steel is considered by Bai-Wierzbicki model, in which the effects of Lode angle and stress triaxiality on fracture of steel are accounted for. The Bai-Wierzbicki model is imported into software ABAQUS by a user-defined subroutine. The CCDs of 2-D steel frame, 3-D steel bare frame, and 3-D steel frame with floor slab due to an interior column loss are compared. The effects of beam span, beam height, slab thickness, and slab aspect ratio on the CCD of 3-D steel frame are studied. For steel frame with different slab span-to-thickness ratios, explicit calculation formulae are established to calculate the CCD of steel frame. It is found that due to the existence of floor slab, the CCD of steel frame is significantly reduced. A larger span-to-depth ratio for steel beam ensures a greater CCD of steel frame. For a certain slab span-to-thickness ratio, the CCD-to-depth ratio of steel beam is almost linear against the span-to-depth ratio of steel beam. Moreover, the CCD of steel frame increases when the slab aspect ratio increases.

Influence of parameters in flexural behavior of composite slabs

Composite steel–concrete deck slabs are used in floor construction in steel-framed buildings where the connection between steel beam and the concrete slab through shear connectors exploits the best combination of each component. The behavior of composite steel deck slab is investigated based on different parameters such as presence of embossments, shape and thickness of profile sheets, thickness of concrete slab, loading constraints, steel–concrete contact and end anchorages. Performance is evaluated on the basis of load carrying capacity, end slip, and the end anchorage contributions to the behavior of composite deck slabs. The finite element analysis is done using ANSYS software by varying different parameters and the influence factor of each parameter in the performance of composite deck slab is found by regression analysis and finally experiments are conducted to validate the study. Based on the parameters studied the trapezoidal sheets of 1.2 mm thickness with stiffeners shows a better performance.

Shear Strength Prediction of Reinforced Concrete Two-way Thick Slabs: Comparison between Experimental and Analytical Studies

This paper describes an attempt to perform analytical studies on shear strength prediction of reinforced concrete two-way thick slabs. To this end, twenty test data from four groups of researchers were adopted and compared against the shear strength predictions from five shear design equations (i.e., ACI 318-14, ACI 318-19, EC2, CSA, and SMCFT). The ability of these equations to provide accurate prediction was evaluated based on the ratio of test-to-calculated shear strength, coefficient of variation (COV), and distribution of test data against the equality line. From the results presented, it was shown that each shear design prediction varied considerably from one another. Regarding the accuracy, it was shown that the SMCFT design method was able to predict the shear strength more accurately and proved the development of theoretically-sound shear design with a simple and straightforward procedure worked well in this case. It was also shown that improved prediction was able to be captured by ACI 318-19 compared to its preceding version of ACI 318-14. ACI 318-19 was also shown to demonstrate more conservative predictions which were more comparable to SMCFT.

Half‐Integer Topological Charge Polarization of Quasi‐Dirac Bound States in the Continuum

AbstractThe non‐trivial polarization topology of bound states in the continuum (BICs) provides new strategies in nanophotonics. The polarization topology depends on the geometric parameters and energy‐momentum dispersion of the system and can be engineered to add specific functionalities for light molding. Herein, such a possibility is investigated by studying the topology of the polarization states associated with the optical field radiated by BICs when Dirac‐cone‐degeneracy is lifted. The opening of a pseudogap in the Dirac cone dispersion of square‐lattice dielectric photonic crystal slabs is achieved by tuning the slab thickness. First, the emergence of half‐integer topological charges without the requirement of BIC annihilation is theoretically shown, which instead occurs when in‐plane inversion symmetry is broken. Then, using spin‐to‐orbital angular momentum conversion, the theory of half‐integer topological charges mediated by BICs is demonstrated and experimentally proved. The same device is able to give rise to vortices with different orbital angular momentum depending on the way it is illuminated, thus improving the potential of optical multiplexing. In addition, the additive character of the topology‐induced phase‐vortex generation is finally demonstrated for both integer and half‐integer charges using also vortex states as input beams, which is of relevance for information delivery.

Prospects of the use of high-tension fiber concrete as the basis for the formation of protective shelters and fortification structures during the russian-ukrainian war

This article analyzes the current state of protective shelters and fortification structures, foresees the modern possibilities of using fastening and basalt-type structures to increase the stability of concrete fortifications both during the construction of buildings for the protection of the civilian population, and for the creation of dugouts, fortifications and fire structures for the protection of personnel in accordance.
 Studies of the physical and mechanical properties of fiber concrete modified with plasticizers and active mineral additives using basalt and polypropylene fibers have shown that their introduction has a positive effect on the strength characteristics of concrete. The compressive strength of fiber concrete at day 28 increases from 61.4 to 77.0 and 96.2 MPa, respectively, and the flexural strength from 7.4 to 12.7 and 13.8 MPa, respectively.
 For the production of reinforced concrete protective materials, it is more effective to create hybrid high-strength concrete using fibers of different nature, followed by the formation of a reinforced concrete slab of the appropriate size. At the same time, the standard provides for the manufacture of prefabricated reinforced concrete elements of fortification structures and platoon support points of wall panels of the SP-1, SP-2 type and floor slabs PP-1 with a thickness of at least 300 mm from heavy concrete of strength class C32/40 with the use of plasticizers and active chemical additives.
 However, when using the obtained hybrid fiber concrete with strength class C50/60 and using a reinforcing mesh according to the calculated data, it is possible to reduce the effective thickness of the fiber concrete slab to 27.5 cm installation of fortification.
 The use of a reinforcing mesh in a complex with basalt fiber provides increased resistance of fiber concrete to the action of a high-speed impact due to an increase in the density of the cementing matrix as a result of a decrease in water consumption, as well as due to spatial three-dimensional reinforcement with dispersed basalt fiber. As a result of the mutual combination of the strength characteristics of the concrete matrix at the micro- and macro-levels in hybrid fiber concrete, it is possible to reduce the thickness of reinforced concrete elements and reduce the weight of the protective structure while meeting the requirements of the standards for such fortifications. An increase in the strength of cement stone occurs due to a decrease in the concentration of stresses in places of local stresses and a redistribution of energy throughout the volume of the material.
 The conducted studies of modern hybrid high-strength concrete with basalt fiber create new opportunities for the creation of protective concrete fortifications and fortification structures.

Case Study: Effect of mechanical short-circuiting of isolation pads on rooftop equipment noise and vibration transfer to spaces below.

The authors conducted investigations into noise from large rooftop air source heat pump (HP) equipment to student housing units below in a new concrete building. The investigation included both airborne noise and vibration measurements on the roof and in the dwelling units below. A total of five, 18-Ton devices were mounted on a foam-filled concrete housekeeping pad resting on an 8-inch thick PT structural slab and isolated by means of spring mounts fitted with neoprene isolation pads below their baseplate. The dwelling units below had exposed concrete at the ceiling, shear walls, and columns. Noise from the HPs were waking residents in the units directly below the equipment. After a number of adjustments to the spring isolation mounts to eliminate bindings and mechanical short-circuits, the investigation showed that vibration was also being transmitted to the building structure from the isolator base plates through the anchor bolts, bypassing the noise pads below the baseplate. Removal of this secondary short-circuit resulted in noticeable reductions in both noise and vibration at the spaces below, highlighting the need for careful adjustment and the provision of additional isolation elements in the installation.

Laboratory measurements on replaceable jack-up systems

Floating floor systems are part of state-of-the-art modern building technology. They are an efficient option to improve the acoustical performance of buildings and can be part of box-in-box systems installed in high-performance spaces. There are many types of high-performance floating floor types, one of which is a jack-up system that guarantees that the floor is decoupled from the structural floor. With these systems, once the concrete has cured, the isolated slab is raised off the structure to the required void depth using pre-cast boxes. These boxes allow for easy adjustment of the final floor height and, if the use of the room or load conditions change in the future, can also allow the replacement of the isolators inside them. Replaceable and inspectable acoustical floor systems are perceived as systems with lower sound insulation (airborne noise) than traditional floating floor or non-replaceable jack-up systems. To measure airborne sound reduction and impact noise isolation of replaceable jack-up systems and confirm factors that can influence its performance, CDM Stravitec invested in a testing campaign, where measurements were made considering many variables, such as: concrete floating slab thickness; bearings type, air void depth, steel lid installed on top of each box and insulation material installed in the air void. This paper will present the

Clinical Characterization of a Table Mounted Range Shifter Board for Synchrotron-Based Intensity Modulated Proton Therapy for Pediatric Craniospinal Irradiation.

Purpose: To report our design, manufacturing, commissioning and initial clinical experience with a table-mounted range shifter board (RSB) intended to replace the machine-mounted range shifter (MRS) in a synchrotron-based pencil beam scanning (PBS) system to reduce penumbra and normal tissue dose for image-guided pediatric craniospinal irradiation (CSI). Methods: A custom RSB was designed and manufactured from a 3.5 cm thick slab of polymethyl methacrylate (PMMA) to be placed directly under patients, on top of our existing couch top. The relative linear stopping power (RLSP) of the RSB was measured using a multi-layer ionization chamber, and output constancy was measured using an ion chamber. End-to-end tests were performed using the MRS and RSB approaches using an anthropomorphic phantom and radiochromic film measurements. Cone beam CT (CBCT) and 2D planar kV X-ray image quality were compared with and without the RSB present using image quality phantoms. CSI plans were produced using MRS and RSB approaches for two retrospective pediatric patients, and the resultant normal tissue doses were compared. Results: The RLSP of the RSB was found to be 1.163 and provided computed penumbra of 6.9 mm in the phantom compared to 11.8 mm using the MRS. Phantom measurements using the RSB demonstrated errors in output constancy, range, and penumbra of 0.3%, -0.8%, and 0.6 mm, respectively. The RSB reduced mean kidney and lung dose compared to the MRS by 57.7% and 46.3%, respectively. The RSB decreased mean CBCT image intensities by 86.8 HU but did not significantly impact CBCT or kV spatial resolution providing acceptable image quality for patient setup. Conclusions: A custom RSB for pediatric proton CSI was designed, manufactured, modeled in our TPS, and found to significantly reduce lateral proton beam penumbra compared to a standard MRS while maintaining CBCT and kV image-quality and is in routine use at our center.